Examining the stool of a person or an animal is a sure way to learn a lot about their health and general condition. If you are unwell yourself, then checking your stool is a good way to get some indication of what the source of the problem might be. Two things that are rightly a cause for alarm when doing this are diarrhea and green stool.
One of the main causes of green diarrhea is salmonella. Salmonella is a form of food poisoning caused by bacteria consumed with food that is usually not properly cooked. This then results in constant diarrhea accompanied by other symptoms such as excessive vomiting, mild greenish discolouration of the stool, nausea, dizziness, headaches, weakness and joint and muscle pain. Sometimes there will also be blood in the stool. Dehydration and malnutrition can sometimes Often the disease is self-limiting (meaning it stops of its own accord) after 24-48 hours, but if it persists it can be serious and even fatal. As such doctors will attempt to treat the condition symptomatically, or in some cases use antibiotics (although these have been shown to prolong affects of salmonella on the stools) which are often administered intravenously due to the vomiting.
As is well known, salmonella is mainly carried by poultry and is largely contracted through eating chicken or eggs that have not been properly cooked. However there is a fair amount of controversy surrounding this as a cause, and many people now claim it is perfectly safe and healthy to eat raw eggs. The existence of salmonella is present in only around .001% of eggs, and in this case they are mostly battery hens not tested for the bacteria, and even then most cases of salmonella will be non-threatening. As such, cooking eggs thoroughly is no longer as important as it once was if you are a healthy adult (risk increases in infants and the elderly) and instead it is more important to buy high quality eggs. Chicken itself however should be thoroughly cooked. Check that it is white all the way through and that there is no bleeding by stabbing the meat with a knife or fork while cooking.
The other major cause of green diarrhea is Giardia (Giardia lamblia intestinalis). This is a single celled organism or protozoa that moves via the use of flagella (meaning that under a microscope it resembles a jellyfish or sperm). Rather than being caused by bacteria as is the case with salmonella, Giardi is a parasite that lives in the intestines and survives on stool. Symptoms include mild digestive symptoms, green diarrhea, inflammation, fever, loss of appetite, weight loss, malabsorption, bloating and others. Giardia is contracted again by eating infested meat or drinking unclean water and so avoidance techniques involve regularly washing the hands, thoroughly cooking meat and avoiding unclean water. The parasites are more common in third world countries so if visiting Africa, south Asia or South America it is recommended to take your own food and bottled water. Giardia will be treated with anti-parasitic drugs.