When all is normal, stool color should be brown. The color of stool is sometimes changed by certain kinds of food, but it can also be altered by a medical condition. A variety of factors can cause abnormal stool color in a range of hues including green, yellow, red, black, tan, and light clay-colored.
Green stool is frequently the result of a harmless dietary cause. Spinach is among the most common culprits which cause green stool. Other similar dark green vegetables can have a similar effect. Green stool tends to be most common on and after St. Patrick’s day, when many people celebrate by drinking and eating food which has been dyed green. Whether during the holiday or at any time of year, when food dye is the cause of green stool, there is no cause for concern as all should return to normal within a few days.
The cause of abnormal stool color may be an issue in bile secretion. According to the Mayo Clinic, clay-colored or white stool may be caused by a condition of the liver like hepatitis or biliary cirrhosis. White stool can also indicate an issue in the gallbladder or the small intestine. If stool is yellow, it could point to problems involving the absorption of fat. Light or white stool can be harmless, as it can be caused by some medications, but medical advice should be sought if it appears.
The causes of abnormal stool color can be benign. Red or black stool often means blood, but it can be harmless in certain situations. According to the University of Michigan Health System, iron supplements and Pepto-Bismol or other bismuth-containing products can temporarily cause black stool. However, bright red stool or black stool can indicate the presence of blood. When stool is red or black, it is time to see a doctor.
Blood in stool can be indicative of many possible medical conditions. Dark black stool is often caused by an issue with the upper gastrointestinal tract, per the UCLA Health System. A stomach ulcer or inflammation (gastritis), bowel ischemia, or an issue involving the esophagus can cause dark bloody stool. Blood red stool is generally related to an issue with the lower gastrointestinal tract. Hemorrhoids are frequently responsible for bright red stool. Anal fissures, diverticulitis, inflammatory bowel disease, and a few other conditions can also cause blood red stool.
While stool is typically brown, various dietary and medical conditions can cause abnormal stool color. Green stool is usually the result of recent diet, but white stool, yellow stool, red stool, and black stool are frequently caused by medical conditions. Anyone with questions or concerns about unusual stool color or blood in stool should talk to their doctor. In particular, if a change in stool color or appearance is accompanied by any other noticeable symptoms, seek medical attention as soon as possible.