Stools normally have an unpleasant odor. Most of the time, the odor is familiar. Stools that have an extremely bad, abnormal odor may be due to certain medical conditions. Foul-smelling stools also have normal causes, such as diet changes.

Causes may include:

• Celiac disease (also called celiac sprue)
• Crohn disease
• Chronic pancreatitis
• Cystic fibrosis
• Intestinal infection
• Malabsorption
• Short bowel syndrome
• Blood in stool from stomach or intestine

Home care depends on what is causing the problem. Things you can do include:

• Follow your health care provider's instructions.
• If you have been given a special diet, stick to it closely.
• If you have diarrhea, drink more fluids so you do not get dehydrated.

Contact your provider if you have:

• Black or pale stools often
• Blood in the stool
• Changes in the stool related to diet
• Chills
• Cramping
• Fever
• Pain in the abdomen
• Weight loss

Your provider will perform a physical exam and ask about your medical history. Questions may include:

• When did you first notice the change?
• Are the stools an abnormal color (such as pale or clay-colored stools)?
• Are the stools black (melena)?
• Are your stools hard to flush?
• What sort of diet have you eaten recently?
• Does a change in your diet make the smell worse or better?
• What other symptoms do you have?

The provider may take a stool sample. Other tests may be needed.

Foul-smelling stools; Malodorous stools

Höegenauer C, Hammer HF. Maldigestion and malabsorption. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. 11th ed. Philadelphia, PA: Elsevier; 2021:chap 104.

Nash TE, Hill DR. Giardiasis. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 330.

Updated by: Michael M. Phillips, MD, Emeritus Professor of Medicine, The George Washington University School of Medicine, Washington, DC. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.