Nausea and diarrhoea after eating: what should you know?

Food poisoning can begin after contaminated food and may cause cramps, vomiting, or fever. Gastroenteritis can spread between people and may cause watery stools with nausea. Acid reflux or gastritis may cause upper-abdominal discomfort and queasiness, while gallstones can cause pain after a rich meal. A repeated pattern with a particular food may point to intolerance rather than infection. The meal, onset, stool appearance, pain, and other affected people help a clinician narrow the cause.

Sip water or an oral rehydration drink frequently, and return to light foods when tolerated. Avoid alcohol and foods that clearly worsen symptoms. Wash hands with soap and water, avoid preparing food for others while unwell, and note what you ate and when symptoms started. Do not take an anti-diarrhoeal medicine if you have blood in the stool or a high fever without medical advice.

Seek urgent care for severe or worsening abdominal pain, blood or black stool, fainting, confusion, or inability to keep fluids down. Arrange medical advice if symptoms recur after meals, dehydration signs appear, or diarrhoea continues beyond a short illness. Children, older adults, pregnant people, and those with long-term conditions may need earlier assessment.

Ask whether testing is needed, which foods or medicines might be contributing, and how to replace lost fluids. Tell the clinician about travel, shared meals, fever, blood in stool, recent antibiotics, and any ongoing weight change.