How common is diarrhoea in food intolerance?

Food intolerance describes difficulty processing a food or ingredient rather than the immune reaction seen in a food allergy. The resulting bowel symptoms can include loose stools, bloating, wind, cramps, or urgency. Symptoms may appear after a particular food, but the timing and amount can vary. Diarrhoea can also result from infection, medicines, anxiety, or a bowel condition, so a food link is a clue to discuss rather than proof of intolerance.

Keep a food and symptom diary that includes meals, drinks, ingredients, symptoms, and the time they occur. Take this record to a clinician or registered dietitian. Avoid cutting out several food groups at once without professional guidance, because this can make it harder to identify a trigger and may reduce nutritional variety. A structured elimination and reintroduction plan may be suggested after other causes have been considered.

Arrange an appointment if symptoms are persistent, recurrent, waking you from sleep, or linked with weight change, fatigue, or ongoing pain. Seek urgent help for blood in stool, black stool, severe abdominal pain, trouble breathing, swelling of the lips or tongue, fainting, or dehydration. Breathing or swelling symptoms can indicate an allergic reaction rather than an intolerance and need immediate assessment.

Ask whether your pattern suggests intolerance, allergy, infection, or another digestive condition; which foods should be recorded; and whether a dietitian can help. Bring details of any reactions, including skin symptoms, wheeze, swelling, and the exact foods eaten.