Bile-acid diarrhea
Content date: 13 November 2026
Excess bile acids reaching the colon can cause watery diarrhea and urgency. Symptoms may resemble IBS, but assessment and treatment need an appropriate individual plan.
Your next step
Record your diarrhea pattern, any previous gallbladder or bowel surgery and your medicines. Discuss the cause and suitable tests with your clinician.
Get urgent help: Seek urgent care for heavy bleeding or black tarry stool, severe pain, repeated vomiting or severe dehydration with dizziness or little urine. Do not automatically attribute these to bile acids.
What do bile acids do?
- Bile acids help digestion and most are normally reabsorbed. Excess amounts reaching the colon can increase water and bowel activity.
- The problem can occur without previous surgery, with disease or removal of the end of the small bowel, or after gallbladder removal. Not all diarrhea after surgery is caused by bile acids.
How is the cause assessed?
- The clinician reviews symptoms, medicines and surgery, and assesses other causes of diarrhea. Symptoms can resemble diarrhea-predominant IBS.
- Tests such as SeHCAT or fasting serum C4 may be considered where available and suitable. Ask what is available locally; not everyone needs the same tests.
- Improvement with a medicine alone does not establish a certain diagnosis; the clinician interprets it within the full assessment.
How is it treated?
- A clinician may prescribe a bile-acid binder such as cholestyramine. The medicine and dose depend on your case; do not start it yourself.
- Constipation or bloating may occur. Review benefit and troublesome effects with the team instead of increasing doses without advice.
- Treatment may affect absorption of other medicines; ask the pharmacist for a spacing schedule that fits your complete medicine list. Nutritional or vitamin monitoring may be needed in selected cases.
Food and special situations
- Adjusting dietary fat may help some people. A dietitian can tailor this, especially with low weight or malabsorption; do not eliminate all fat.
- Extensive small-bowel resection needs specialist planning; a bile-acid binder is not automatically suitable for everyone after surgery.
What should I record for follow-up?
- Bowel frequency, urgency, relation to meals, weight and dehydration symptoms.
- Medicine names and timing, whether diarrhea improves and whether constipation develops. Keep a clear follow-up plan.
When to get help
Seek urgent care for heavy bleeding or black tarry stool, severe pain, repeated vomiting or severe dehydration with dizziness or little urine. Do not automatically attribute these to bile acids.
Seek review for ongoing diarrhea or weight loss, troublesome constipation during treatment, or unclear timing with your other medicines.