Changes in stool (feces) color are often harmless and reflect dietary influences. The normal brown color of stool occurs due to the presence of bilirubin. Bilirubin is formed as a breakdown product of hemoglobin (from red blood cells) in the liver and is secreted into the bile, which enters the intestines. If the intestinal contents travel at a normal speed, chemical changes in bilirubin produce stool that is light to dark brown. The stool may appear green if the intestinal contents pass through the bowel more rapidly.
Changes in the color of stool are common and are generally not significant if the changes are noted from one stool to the next and are not persistent. However, changes in the color of stool can also be caused by a number of minor to serious medical conditions and can occur with certain medications. Changes in stool color that are persistent and do not occur in only one stool may signal the presence of a medical condition and should be evaluated.
Certain persistent changes in stool color are characteristic for specific conditions:
- black, foul-smelling stool: intestinal bleeding (typically from the stomach and upper small intestine) due to ulcers, tumors; ingestion of iron or bismuth
- maroon stool: intestinal bleeding (from the middle intestine or proximal colon) due to ulcers, tumors, Crohn's disease, ulcerative colitis
- clay-colored stool: lack of bile due to blockage of the main bile duct
- pale yellow, greasy, foul-smelling stool: malabsorption of fat due to pancreatic insufficiency, as seen with pancreatitis, pancreatic cancer, cystic fibrosis, celiac disease
Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.
Main Article on Stool Color & Texture Changes
Pictures, Images, Illustrations & Quizzes
Celiac Disease Quiz: What Is Celiac Disease?
Could celiac disease be the cause of your tummy troubles? Take the Celiac Disease Quiz to learn what certain foods may be doing...
Celiac Disease: Symptoms, Gluten in Foods, Gluten Allergy Tests, and More
Do you suffer from celiac disease? Learn about diet, symptoms, diagnosis, and treatments for this digestive disorder that occurs...
Crohn's Disease Causes, Symptoms, Diet
What is Crohn's disease? Get more information on this digestive disorder and how Crohn's can affect your diet. Learn more about...
Crohn's Disease Quiz
What causes Crohn's disease? What are the symptoms of Crohn's disease? How is Crohn's treated? Take this quiz to get the facts...
Inflammatory Bowel Disease (IBD) Causes, Symptoms, Treatment
What is inflammatory bowel disease? IBD can include Crohn's disease and ulcerative colitis. Learn more about testing, treatments,...
Ulcerative Colitis Quiz: Diet, Symptoms & Treatment
What is ulcerative colitis and what risks are associated with suffering over the long term? Take this Ulcerative Colitis Quiz to...
Ulcerative Colitis Symptoms, Causes, and Treatment
Ulcerative Colitis is a form of inflammatory bowel disease and is slightly different than Crohn's disease. Your diet can impact...
Causes of Stool Color & Texture Changes
H. pylori (Helicobacter Pylori ) Infection Symptoms, Test, Treatment
Helicobacter pylori (H. pylori) is a bacteria that causes chronic inflammation (gastritis) of the inner lining of the stomach,...
Anal cancer, cancer located at the end of the large intestine, has symptoms that include anal or rectal bleeding, anal pain or...
An anal fissure is a small tear or cut in the skin lining of the anus. Pain and/or rectal bleeding during bowel movements are...
Blood in the Stool (Rectal Bleeding)
Blood in the stool or rectal bleeding (hematochezia) refers to the passage of bright red blood from the anus. Common causes...
Celiac disease is a condition in which a person has inflammation of the small intestinal mucosa when exposed to gluten in the...
Cholera is an infectious disease characterized by intense vomiting and profuse watery diarrhea and that rapidly lease to...
Crohn's Disease (Symptoms, Causes, Diet, Treatment, Life Expectancy)
Crohn's disease is a chronic inflammatory disease, primarily involving the small and large intestine, but which can affect...
Crohn's Disease vs. Ulcerative Colitis (UC): Differences and Similarities
Crohn's disease and ulcerative colitis are diseases that cause inflammation of part of or the entire digestive tract (GI)....
Cystic fibrosis is a disease of the mucus and sweat glands. Cystic fibrosis is an inherited disease. The outcome of the disease...
E. coli (0157:H7) (Symptoms, Treatment, Prevention)
There are many types of E. coli (Escherichia coli ). E. coli can cause urinary tract and bladder infections, or lead to sepsis. E...
Exocrine Pancreatic Insufficiency (EPI)
Exocrine pancreatic insufficiency or EPI is a condition in which a person's pancreas can't produce or secrete certain enzymes...
Gallbladder cancer is a rare form of cancer with symptoms that include jaundice, abdominal pain, fever, nausea and vomiting,...
Gastritis (Symptoms, Pain, Home Remedies, and Cure)
Gastritis (acute and chronic) is an inflammation of the lining of the stomach Some people have no gastritis symptoms, but when...
Hepatitis (Viral Hepatitis, A, B, C, D, E, G)
Hepatitis is most often viral, due to infection with one of the hepatitis viruses (A, B, C, D, E, F (not confirmed), and G) or...
Hepatitis B (HBV, Hep B)
The hepatitis B virus (HBV, hep B) is a unique, coated DNA virus belonging to the Hepadnaviridae family of viruses. The course of...
Hepatitis C (HCV, Hep C)
Hepatitis C is an inflammation of the liver due to the hepatitis C virus (HCV), which is usually spread by blood transfusion,...
Inflammatory Bowel Disease (Intestinal Problems of IBD)
The inflammatory bowel diseases (IBD) are Crohn's disease (CD) and ulcerative colitis (UC). The intestinal complications of...
Internal bleeding occurs when an artery or vein is damaged and blood to escapes the circulatory system and collects inside the...
Is C. diff (Clostridium difficile) Contagious?
C. diff, or Clostridium difficile, is a bacteria that infects the colon. C. diff bacteria can be found on furniture, bathroom...
Is Colitis Contagious?
Colitis is a term that us used to describe inflammation of the colon. The terms enteritis, proctitis, and inflammatory bowel...
Is Hepatitis A Contagious?
Hepatitis means inflammation of the liver. Hepatitis A is one type of hepatitis. Hepatitis is transmitted through person to...
Jaundice (Hyperbilirubinemia in Adults)
Jaundice (hyperbilirubinemia) in adults may be caused by a variety of medical diseases or conditions. Some cases of jaundice can...
Lactose intolerance is a common problem where a person's digestive system cannot digest lactose. Signs and symptoms include:...
Pancreatic cancer is a malignant tumor of the pancreas. Pancreatic cancer has been called a "silent" disease because early...
Pancreatitis (Acute, Chronic) Symptoms, Causes, Diet, and Treatment
Pancreatitis is a rare disease in which the pancreas becomes inflamed. There are two types of pancreatitis: acute and chronic....
Peptic Ulcer (Stomach Ulcer)
Peptic or stomach ulcers are ulcers are an ulcer in the lining of the stomach, duodenum, or esophagus. Ulcer formation is related...
Salmonella infection (salmonellosis) is typically caused by the consumption of contaminated foods. Symptoms of salmonellosis...
Shigellosis is a disease caused by the Shigella bacteria. Bloody diarrhea, stomach cramps, and fever are common symptoms. Mild...
SIBO (Small Intestinal Bacterial Overgrowth)
Small intestinal bacterial overgrowth (SIBO) refers to a condition in which abnormally large numbers of bacteria (at least...
Though the cause of stomach cancer is unknown, risk factors for stomach cancer include diet, H. pylori infection, smoking age,...
Ulcerative colitis is a chronic inflammation of the colon. Symptoms include abdominal pain, diarrhea, and rectal bleeding....
Other Causes of Stool Color & Texture Changes
- Barium (From a Radiographic Test)
- Bile Duct Cancer
- Bismuth-Containing Medicines (for Example, Bismuth Subsalicylate [Pepto-Bismol])
- Bleeding Into the Intestines
- Bleeding Into the Stomach or Esophagus
- Consumption of Black Licorice
- Consumption of Certain Fruits and/or Vegetables (for Example, Beets, Spinach, and Cranberries)
- Food Dyes (Particularly Red and Green)
- Infectious Colitis
- Intestinal Malabsorption
- Iron Supplements
- Tumors of the Pancreas or Pancreatic Duct
- Tumors or Polyps of the Stomach or Intestines
Examples of Medications for Stool Color & Texture Changes
Subscribe to MedicineNet's General Health Newsletter