When to see a doctor for blood & mucus in the stool

Stool changes depending on what you have eaten or if you have suffered from any illness, such as food poisoning, gastroenteritis, influenza or Delhi belly. On average, you are supposed to pass solid stool with no mucus or blood. Anytime you see blood in your stool, you should notify your physician.

Normal Stool

Normal stool is medium in size and the colour of plain cardboard. You should not have to strain for it to exit the body and it should cause very little discomfort or pain. The consistency should be like toothpaste and it should be about 4 to 8 inches long. Normal stool does not have blood or mucus in it.

Blood in the Stool

Bright red blood comes from your rectum. It can appear as drops in the toilet, a smudge on tissue or as a streak on the stool. Causes of bright red blood in the stool are anal fissures (small tears in the skin around the anus), rectal polyps (small growths lining the inside of the colon), cancer of the rectum or haemorrhoids. Symptoms of haemorrhoids are itching, pain, burning and throbbing.

Bleeding can also appear dark brown, black or tarry. Peptic ulcers, overuse of alcohol, overuse of aspirin, broken blood vessel in the colon or use of anti-blood clotting medications can cause stools of these colours.


In addition to the bleeding and mucus, you may also feel pain when passing a bowel movement and you may feel feverish. Fever and a general feeling of illness may be symptoms of serious conditions such as ulcerative colitis, Crohn's disease or dysentery. These are inflammatory bowel diseases. It is important to have yourself checked out by a physcian if you have any of these symptons, as inflammatory bowel disease can produce mucus and pus in your intestines. Colon cancer can also be detected if your bowels are screened.

If you notice dark blood in your stool, call your physician immediately. Never try to diagnose these problems yourself. When seeking medical help, make sure you have the names of all medications you are on, and any medical conditions you may be suffering from.

If you have symptoms such as fainting, weakness, sweating or large amounts of blood in your stool seek emergency care immediately.

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About the Author

April Khan is a medical journalist who began writing in 2005. She has contributed to publications such as "BBC Focus." In 2012, Khan received her Doctor of Public Health from the University of Medicine and Dentistry of New Jersey. She also holds an Associate of Arts from the Art Institute of Dallas and a Master of Science in international health from University College London.