Constipation and Diarrhea

No organ of the body is as misunderstood and fussed over as the digestive tract. It has been purged, irrigated, and massaged, all in the name of an obsessive concern with the daily bowel movement. Many believe that the waste matter left after digestion must be expelled twenty-four to forty-eight hours after the food is eaten. The fallacy of this notion was revealed in an experiment supervised by the late Walter C. Alverez, M. D. A group of healthy young medical students swallowed sets of gelatin capsules containing many small glass beads. Two of the students passed about 85 percent of the beads in twenty-four hours; most took four days to eliminate three-fourths of the beads; some passed only half of the beads in nine days. Those who passed the majority of the beads in twenty-four hours had poorly formed stools containing undigested material. Those with a slower rate usually had well-formed stools showing evidence of good digestion. Some of the participants with the slower rates had believed that they were constipated.

Alverez likened the colon and its fecal contents to a railroad siding on which three freight cars are standing. Every day a new car arrives and bumps the end one off, leaving three again. But occasionally one arrives at the siding with such force that it bumps all three off, and then three days must elapse before the siding is full again. In other words, when the colon is cleaned out by a purge or large bowel movement, nothing more should be expected for several days.

Nor does everyone operate on a once-a-day schedule. It is common to find people in perfect health who defecate two or three times a day, and others who have a single evacuation every two or three days. There are many individuals who have bowel movements at still longer intervals without the slightest ill effect.

Constipation, then, cannot be defined in terms of a daily bowel movement, but must be related to each person’s normal functioning. What’s more, missing a few bowel movements should cause no alarm. After a few days, things generally return to normal, and the rhythm is reestablished.

Indeed, most cases of constipation cure themselves without intervention. This is fortunate because, commercial advertising to the contrary, there is no such thing as a perfect, natural, or entirely harmless laxative.

A mild laxative can be beneficial in some instances. When, for example, there is temporary difficulty in evacuation due to emotional stress, traveling, or change in diet, there is no harm in taking a mild laxative for a day or two. And in some cases of chronic constipation—if it definitely has been proved to exist and there is no organic cause—a physician may suggest a laxative to help relieve the condition. But the widespread overdependence on laxatives, which supports the sale of more than 700 different over-the-counter (OTC) products, can be explained only by an equally widespread misunderstanding of constipation and the drugs used to treat it.

All types of laxatives have some disadvantages. Moreover, the distinction that the advertisers make between mild laxatives and harsh cathartics is highly deceptive. Any material taken by mouth to promote evacuation of the intestine is a cathartic drug; a laxative is simply a mild cathartic. But the strength of a laxative’s cathartic effect can vary greatly between people and in the same person at different times.

Laxatives have no doubt contributed to the ills and discomforts of humanity more than the condition they are supposed to relieve. Instances of a ruptured appendix with peritonitis have been recorded in patients who assumed their abdominal pain was caused by constipation and so dosed themselves with laxatives. But constipation is rarely associated with abdominal pain. Nor does the presence of pain mean the bowels need to be cleaned out.

Many people have heard that, at the beginning of a cold or an attack of grippe, flu, or acute tonsillitis, a cathartic should be taken. This myth is a holdover from the Middle Ages when “a dose of the salts” was supposed to cure everything from ague to plague. Yet catharsis does not prevent, cure, or lessen the severity of these or any other illnesses. In acute illness, constipation may simply be associated with dehydration, poor intake of food, or prolonged inactivity. To purge a patient who is already suffering from depleted fluid reserves is foolish—and may even be disastrous.

Irritable Bowel Syndrome: Alternating Constipation and Diarrhea

Most often, bowel dysfunction reflects emotional stresses. Such influences on the colon can cause opposing responses in different people—or even in the same individual. In one person they may speed up bowel transit time for ingested foodstuffs and cause diarrhea with occasional mucus in the stool. In another they may slow bowel activity and cause hard, dry, and infrequent stools. In a third they may lead to intestinal spasms perceived as painful abdominal cramps, with alternating periods of diarrhea and constipation.

When these conditions persist or recur, they are known collectively as irritable bowel syndrome. This is the likely diagnosis in the case of longstanding bowel complaints associated with worry, fear, and anxiety. The irritable bowel syndrome is a complex disorder probably triggered by many factors, particularly emotional upsets. Irregular peristalsis (the wavelike, propelling contraction of the intestinal tract) results not only in abdominal pains and distention but also in excessive passage of gas; and hard stools often alternate with looser stools. Management of the irritable bowel syndrome consists first of ruling out a definable cause. Careful selection of diet, including an increase of fiber content, can be helpful. Reducing stress through regular exercise and relaxation techniques is important. Professional counseling to treat anxiety or other underlying psychological disorders may be necessary. (Bloody stools, which are not usually associated with the irritable bowel syndrome, always require consultation with a physician.)

The irritable bowel syndrome is no longer considered the only cause for complaints of bloating, gaseous distention, and intermittent loose stools. It has been shown that for some people a more likely explanation may be what formerly was called an intestinal “allergy.” A physician may discover through careful questioning that the discomfort is due to a food intolerance. A frequent cause is the lack of an intestinal enzyme—lactasewhich is essential for the proper digestion of milk products. These foods tend to precipitate episodes of abdominal discomfort. The ingestion of certain other foods can cause similar patterns such as florid diarrhea, experienced by patients with nontropical sprue and celiac disease—an intestinal malfunction caused by intolerance to gluten (the insoluble protein constituent of wheat and other grains).

Unfortunately, the symptoms of an irritable bowel are not always evident. For example, the emotional factors responsible for bowel dysfunction may not be obvious, so that sufferers may not be able to know that their constipation or diarrhea is of this type. This is another reason why proper diagnosis is important before a course of treatment for chronic constipation or diarrhea is begun.

Causes and Treatment of Diarrhea

The affliction commonly referred to as “acute gastroenteritis” usually involves two or three days of diarrhea, along with fever and general malaise. It is thought to be viral in origin. Healthy individuals are able to withstand such illness with only minor discomfort. The very young and the very old, regardless of their health, fare less well. Because they are especially sensitive to the need for adequate fluid replacement, some may even require hospitalization.

Most attacks of diarrhea tend to be self-limited, with the symptoms relieved (with or without medication) in a few days. However, diarrhea can be protracted, lasting more than a week. In the beginning stages, underlying causes of protracted diarrhea—such as giardiasis, amebic dysentery, Crohn’s disease, or ulcerative colitis—may be difficult to diagnose. Because specific therapy for such diseases must often await diagnosis, it is important during a prolonged bout of diarrhea to have microscopic and bacteriological examinations made of the stool, as well as a sigmoidoscopic examination of the rectum, in which a physician may directly observe the rectum and lower bowel through a flexible, lighted tube called a sigmoidoscope. X rays of the bowel also may be necessary.

If an attack of diarrhea does not subside in a day or so, or if diarrhea is accompanied at any time by fever, severe abdominal pain, or bloody stools, don’t self-medicate. Consult a physician. In any case, a person suffering from diarrhea should drink plenty of liquids to offset loss of fluids in the watery stools. Decreasing the amount of roughage (or bulk producers) in the diet—for example, cutting out most raw fruits and raw vegetables—and following the time-honored treatment of rice and bananas may reduce the severity of the attack.

OTC preparations commonly used for acute diarrhea, such as kaolin/pectin mixtures (Kaodene and Kaopectate, among others), are less effective than antidiarrheal drugs containing narcotics, which require a prescription in most states. Physicians may prescribe diphenoxylate (Lomotil) or loperamide (Imodium). (Imodium in liquid form is now available OTC; capsules are still available only by prescription.) These two drugs provide relatively prompt relief from diarrhea. In the amounts used for occasional diarrheal attacks, they should present no problem of dependency.

The use of diphenoxylate and loperamide is inadvisable for infants and young children. Toxicity has been observed with minimal dosage. Nor have they been proved safe for use by pregnant women. And they should be used with caution, if at all, in acute infectious diarrhea, since some experts believe these medications can actually prolong the disease.

Some medications frequently cause loose, watery bowel movements. The most common offenders include such antibiotics as erythromycin, ampicillin, and tetracycline. Also capable of provoking diarrhea are some magnesium-containing antacids and large doses of ascorbic acid (vitamin C).

Causes and Treatments of Constipation

When true chronic constipation is present, it may result from overemphasis on toilet training in childhood, crowded living conditions, poor diet, or similar behavioral factors. Something as simple as improper toilet habits is frequently an underlying cause. When the urge to defecate is disregarded, the sensation passes. It usually returns again during the day, especially after a meal, but if the call is consistently disobeyed day after day, the rectum may eventually fail to signal the need for evacuation. The result may be severe constipation.

Why is the call disregarded? It may be suppressed, or it may be overwhelmed by other and stronger stimuli, similar to loss of one’s appetite on hearing bad news. It also may be neglected because of the pressure of school or work, or perhaps because there is a morning train to catch, or only one bathroom for a large family.

Many commonly used OTC and prescription drugs are also apt to cause constipation. Antacids may often be a source of difficulty. Among prescription drugs the most notorious offenders are narcotics such as codeine, opium, and oxycodone (the active ingredient in Percocet and Percodan). Another class of compounds capable of causing constipation includes those affecting the parasympathetic nervous system. Among these drugs are gastrointestinal antispasmodics such as propantheline (Pro-Banthine), antidepressants such as imipramine (Tofranil), and major tranquilizers such as chlorpromazine (Thorazine). Should constipation become a severe side effect, a physician may decrease dosage or switch to another medication.

The misuse of laxatives is another important cause of chronic constipation. Whatever the original reason for using a laxative, repeated purging in time brings changes in the lining and muscle tone of the bowel; the lining can become irritated and inflamed, and with long-continued catharsis muscular reflexes can become so diminished that stronger and stronger stimulation is required to produce activity. Chronic laxative abusers may also unknowingly be depleting their body of potassium, resulting in muscle weakness. Moreover, few users of cathartics have not suffered from fissure of the anus or hemorrhoids. Such ailments often make defecation so painful that the sufferer tends to postpone a visit to the toilet, with the same results as those occurring in a person who is too busy.

A small percentage of patients with constipation may have an organic disease such as diverticulitis or cancer. This cause is most likely to be found in adults who previously have had regular and satisfactory evacuation but then begin to experience a persistent change in the character or frequency of bowel movements. To investigate the possibility of organic disease, a physician may directly observe the rectum and lower bowel through a sigmoidoscope. The physician also may have a radiologist perform a barium-enema X-ray examination to inspect the remainder of the lower bowel. But, to repeat, constipation is not commonly caused by an organic disease. And in general, if constipation has been present for a number of years, the condition probably is not due to disease.

Safe and Effective Laxatives

The Food and Drug Administration (FDA) advisory panel that reviewed OTC laxatives in 1975 judged that 25 percent of the 81 laxative ingredients submitted for review were unsafe or ineffective. Another 20 percent needed further study.

Most of the unsafe and ineffective ingredients are no longer included in the products currently on the market—but, as of this writing, some of the dubious ones are still around. Ingredients judged by the panel to lack “medical or scientific rationale” included vitamins and minerals (as in Geriplex-FS) and capsicum (no longer widely marketed as a laxative). The panel recommended that labels list not only the quantity of each active ingredient in a standard dose but also all inactive ingredients as well. It recommended that ingredients judged unsafe or ineffective or lacking in medical or scientific rationale be eliminated from OTC laxative products.

CU’s medical consultants suggest that you avoid laxatives containing ingredients that act as bowel stimulants, unless advised by a physician. These drugs include phenolphthalein (Alophen, Correctol, Espotabs, Evac-Q-Kwik, Evac-U-Gen, Ex-Lax, Feen-A-Mint Pills, and Laxcaps), senna (Gentlax, Senokot), bisacodyl (Carter’s Little Pills, Dulcolax), and cascara (Nature’s Remedy). All these agents stimulate peristalsis; all can cause severe painful cramping. The FDA panel recommended that stimulant laxatives be labeled with this warning: “Prolonged or continued use of this product can lead to laxative dependency and loss of normal bowel function. Serious side effects from prolonged use or overuse may occur.”

Another class of laxatives that increases peristalsis includes saline (salt) cathartics. The most popular salts used are magnesium citrate (citrate of magnesia), magnesium hydroxide (milk of magnesia), and sodium phosphate (Fleet Phospho-Soda, Sodium Phosphates Oral Solution USP). Results with these laxatives can be dramatic, depending on the dose used. People with chronic kidney disease, who may have difficulty in excreting magnesium, should be wary about using milk of magnesia. People on salt-restricted diets should avoid laxatives containing sodium.

If you must resort to a laxative, CU’s medical consultants recommend that you restrict yourself to a bulk-producing laxative or possibly a stool softener. According to the FDA panel report, “Bulk-forming laxatives are among the safest of laxatives.” Bulk-producing laxatives, such as psyllium (Effer-Syllium, Fiberall, Hydrocil Instant, Konsyl, L. A. Formula, and Metamucil), tend to cause fewer unpleasant side effects than bowel stimulants. Those on salt-restricted diets should note that Effer-Syllium and Metamucil Instant Mix (both regular and orange flavor) contain a considerable quantity of sodium. (Most bulk producers should be taken with a full glass of water to guard against the remote possibility of intestinal obstruction.)

Synthetic cellulose derivatives—methylcellulose and carboxymethyl cellulose sodium—are sometimes used as bulk-forming laxatives, but usually in combination with other active ingredients. Generic versions of these products are also available.

Stool softeners work for some people, but not for all. These detergent products help fluids to penetrate the stool and increase its water content. Docusate sodium (or calcium) sulfosuccinate is the main detergent or softener, and is marketed under such brand names as Afko-Lube, Colace, Coloctyl, Comfolax, docusate sodium, DioMedicone, Dio-Sul, Disonate, Doxinate, Modane Soft, Regutol, and Surfac.

The brand names on this article by no means exhaust the list of laxatives on the market. In addition to the preparations based on a single active ingredient, there is a predictably large contingent of combination-type laxatives. Shoppers may find products combining a stool softener with a bulk laxative, or a bowel stimulant with an emollient. Although the FDA panel would allow some products with two active laxative ingredients (but no more than two) to remain on the market, the panel agrees that a single-ingredient product is safest. As always, consumers are urged to read the label carefully.

The laxative market is swamped with label claims that, in the panel’s opinion, should be changed. A laxative label should not make assertions about general benefits for good health, regularity, or the relief of indigestion, headaches, or “excessive belching.” Instead, it should identify the product as a laxative for the “short-term relief of constipation.” Nor should the label warn against the hazards of constipation, because such warnings are “unproven and thus unacceptable,” according to the panel. Also forbidden would be any suggestion that taking a laxative is somehow natural. The panel points out that taking a laxative is never natural. And the label should not suggest that the laxative is particularly appropriate for individuals of a certain sex or age.

Mineral oil (an emollient) has had many loyal fans, particularly among older people. However, use of mineral oil over time—especially by the elderly or disabled—may lead to lipid pneumonia, a chronic lung condition caused by inadvertent inhalation of oil into the lungs. Because of this and other disadvantages, such as rectal leakage and interference with the body’s absorption of vitamins A, D, E, and K, mineral oil is no longer a laxative of choice. The drawbacks of mineral oil, however, can be minimized by taking it only occasionally in the smallest effective dosage (about one tablespoon for an adult) on an empty stomach and by not lying down for at least half an hour after ingestion. Because the absorption of mineral oil can be facilitated by docusate sodium, these two agents should not be used at the same time.

Yogurt and acidophilus milk were once in vogue for the treatment of bowel disorders, including constipation. The nutritive value of yogurt and other fermented milks is essentially the same as that of the whole milk from which they are made; hence they are good foods. And they can be safely consumed by people who have an intolerance to lactose. But, although fermented milks have occasionally been reported to be successful in the treatment of mild constipation, they usually are not of much value. Nor is there any evidence to support the routine use of vitamin B, vitamin B6, or any other vitamin in the treatment of habitual constipation.

Some people may find it more natural, if not as convenient, to use an enema instead of a laxative. As authorities have been saying for many years, it does seem unreasonable to upset 25 feet of intestine with a cathartic when the trouble is in the last 8 inches—the rectum and the anal canal. An enema consisting of a pint of tepid tap water is generally sufficient. While they are relatively expensive, prepackaged disposable enemas (for example, Fleet) can be a convenience. But too frequent use of enemas—even once a week, for some people—can result in an inability to initiate a bowel movement without an enema. (High colonic enemas, incidentally, are an antiquated, useless, and sometimes harmful procedure. They do not cure habitual constipation or remove “toxins,” and they certainly do not in any way promote health or prolong life.)

Glycerin and bisacodyl (Dulcolax) suppositories have also been employed to stimulate evacuation of the rectum without disturbing the rest of the bowel. Their occasional use does no harm, but most physicians believe that frequent use of suppositories can cause irritation both of the anus and of the mucous membrane of the rectum.

Recommended Treatment of Constipation

Against this background, some rational approaches to the treatment of constipation become clear. For temporary constipation, the obvious thing to do is nothing; let nature take its course, and the condition will resolve itself. If you have been taking laxatives for constipation, the first thing to do is to stop taking them. Many people who have done so at the insistence of a physician have been surprised to find that, after a few days or a week, the bowels begin to move effectively again.

You might find it helpful to add fiber, or roughage, to your diet in the form of fruits, vegetables, breads, and whole-grain cereals. Fiber resists digestion and reaches the large intestine virtually unchanged. There, it speeds the passage of feces through the intestine, lessening the strain of a bowel movement. Fiber also retains water and adds to the bulk, softness, and weight of stool—all factors in easing strain. (Adding liquids to the diet contributes to the softening effect.)

Remember, however, that each person’s digestive system works differently. Some people can eat a high percentage of fiber without the slightest inconvenience. The same meal can cause others distress. If such a diet causes pain, distention, mucus in the stool, or other evidence of irritation, a physician should be consulted.

Among the more valuable foods for fiber are bran, spinach, raw carrots, and whole fruit. Bran, often promoted for the relief of constipation, may be useful particularly to those who do not object to swift and dramatic results. Cereals with the highest bran content include Fiber One and Kellogg’s All-Bran and All-Bran with Extra Fiber. Prunes, the traditional friend of the constipated, provide bulk and contain a chemical that stimulates peristalsis. Peristalsis may also be aided through use of prune extract or prune juice.

The role of exercise in the treatment of constipation has been promoted by many. It may divert one’s thoughts from work or household worries, conferring a sense of relaxation that facilitates a bowel movement. Massaging the abdominal muscles is a waste of time as therapy for constipation. And the value of drinking large quantities of water—even hot water flavored with lemon—has been highly overrated. However, any of these measures may have an important psychological effect.

As stated previously, on certain occasions, a mild laxative for a day or two may help you to overcome a temporary disruption caused by stress, travel, or diet. Your best choice is the mildest laxative that produces results—usually a bulk producer or perhaps a stool softener.

Some people complain of headache or sluggishness, or they just plain worry if they don’t have a regular bowel movement; for such people it may be less harmful to use a laxative once in a while than to fret.

If simple measures don’t clear up constipation within a week or so, the problem requires advice from a physician. Rational treatment must be based on the cause, and that can be established only through physical examination, careful questioning, and perhaps testing. Daily living habits and diet must be taken into account. Often a laxative is prescribed, as a temporary measure, to promote evacuation while the patient tries to reestablish a normal bowel routine. The laxative may then be gradually withdrawn.

Constipation in children requires special consideration. In the majority of cases it is due to oversolicitous attitudes on the part of parents. When a child senses anxiety in a parent about bowel function, the child too may become tense and unable to relax, and relaxation is essential to a normal bowel movement.

If constipation develops in a child, what should be done? A good rule to follow in treating a child’s constipation is “Don’t.” A child will not become ill from a temporary lapse, and in a day or two normal bowel activity usually reestablishes itself spontaneously. If constipation is due to an acute ailment, medical care for the illness—not a laxative—is required. If constipation tends to recur, it may be due to improper diet or bowel habits, and a physician should be consulted. The prohibition of laxatives, suppositories, and enemas for children with constipation cannot be too strongly emphasized.

Pregnant women are especially susceptible to constipation because of the direct pressure of the enlarged uterus on the rectum as well as the relaxing effect of elevated hormone levels on the muscles of the bowel. But a pregnant woman should not routinely take laxatives—or any medication—without consulting a physician. There’s no harm, however, in adding some roughage to the diet.


  1. I hope your website is found by those with numerous questions re: our digestive system, as the coverage is phenomenal, and most everything one cares to know is right here. I feel an added spark of energy having been privvy to this information and will proceed with some of your suggested treatments. Thank you so much. M.S.

  2. Thank you for putting my mind at rest. I became very worried after a flu-like diarrhea that I had for two days, thus cleaning everything out, and now more than two days later no solid movement after the diarrhea stopped. I guess this is normal and that I am not necessarily severely constipated. I have been off of laxatives of any type for over a year but always tend to worry (I have anxiety), so letting nature take its own course after all of this, I presume everything will be back to normal soon given my diet and liquid intake.

  3. This was really helpful, straight forward and personable. This article does not feel vague and out of touch like most medical website information.

  4. Very informative and easy to understand

  5. What a relief to find clear, concise and helpful information. Thank you.

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