What should you know about bile salt diarrhoea?

Bile salt diarrhoea happens when excess bile acids reach the colon and draw in water, causing watery, urgent stools. It may be called bile acid diarrhoea. Some people also notice cramping, bloating, or difficulty reaching a toilet in time. The pattern can continue after meals and may be mistaken for another bowel condition.

Bile acids are made by the liver and released into the small intestine to help digest fat. Most are normally reabsorbed before the bowel contents reach the colon. If reabsorption is reduced, or if bile acids move through the small intestine too quickly, more can enter the colon. The colon responds by secreting water and moving its contents faster, producing loose stools and urgency.

It can occur without an obvious underlying illness, or after surgery affecting the gallbladder or small intestine. It can also be associated with conditions such as Crohn's Disease or Coeliac Disease. Persistent diarrhoea has other possible explanations, including Food Intolerance, Irritable Bowel Syndrome, Gastroenteritis, Food Poisoning, Giardiasis, and Hyperthyroidism, so symptoms alone cannot identify the cause.

Arrange a medical assessment if loose or urgent stools keep returning, especially when the pattern affects daily activities. A clinician may ask about timing after meals, stool appearance, weight change, previous bowel surgery, medicines, travel, and food triggers. They may request blood or stool tests and, when appropriate, arrange further bowel assessment. Keeping a brief record of meals, bowel movements, urgency, pain, and medicines can make the pattern easier to assess.

Drink regularly to replace fluid. During active diarrhoea, oral rehydration solution can help replace water and salts; follow the packet instructions. Do not start a very restrictive diet without advice, because removing many foods can make nutrition harder. If bile salt diarrhoea is diagnosed, a prescriber may recommend a bile-acid binding medicine and review whether it is helping.

Seek urgent medical help for signs of significant dehydration, such as faintness, confusion, very little urine, or inability to keep fluids down. Prompt assessment is also needed for blood or black stools, severe or worsening abdominal pain, a swollen abdomen, high fever, or diarrhoea that is rapidly worsening. Contact a clinician soon if symptoms persist, disturb sleep, cause unplanned weight loss, or begin after recent antibiotics, travel, or bowel surgery.

Useful questions include: Could bile acids be contributing to my symptoms? Which tests are suitable for me? Could a medicine, surgery, infection, or another bowel condition explain the pattern? What should I do if treatment causes constipation or other side effects? When should I arrange a follow-up?