What should you know about foamy diarrhoea?

Bubbles can form when gas mixes with loose stool, particularly during a short-lived infection or after a sudden change in diet. Food intolerance may cause symptoms after a particular ingredient, while coeliac disease can interfere with digestion after gluten exposure. Giardiasis can cause persistent, foul-smelling, greasy or frothy stools, especially after unsafe water exposure. Inflammatory bowel conditions such as Crohn's Disease may cause ongoing diarrhoea with abdominal pain, weight change, or tiredness. Hyperthyroidism can also speed bowel movements, but appearance alone cannot identify a cause.

Replace lost fluids with frequent sips of water or an oral rehydration drink, particularly after repeated stools. Eat small, plain meals as tolerated and avoid alcohol and foods that clearly worsen symptoms. Keep a short record of stool appearance, frequency, foods, travel, medicines, pain, and fever. Do not start a strict gluten-free diet before discussing testing if coeliac disease is a possibility, because changing the diet can affect assessment. A clinician can decide whether stool or blood tests are needed.

Get prompt medical advice for diarrhoea with blood, black stool, high fever, severe abdominal pain, repeated vomiting, or symptoms that do not settle. Urgent help is needed for fainting, confusion, very little urine, a dry mouth with inability to drink, or rapidly worsening weakness. Children, older adults, pregnant people, and those with significant medical conditions may need earlier assessment because fluid loss can become serious more quickly.

Ask whether your pattern suggests infection, intolerance, inflammation, or another digestive problem; which tests are useful; and which foods and fluids are suitable while symptoms continue.