What should you know about sickness and diarrhoea?

Vomiting is forceful emptying of the stomach, while diarrhoea means loose or watery stools. Together they commonly occur with gastroenteritis, food poisoning or another infection. Food intolerance, coeliac disease, Crohn's disease and irritable bowel syndrome can also cause diarrhoea, although vomiting may point to a short-term illness. Giardiasis is another possible infectious cause, especially after exposure to unsafe water. An overactive thyroid can sometimes contribute to frequent bowel movements.

Rest and sip water or an oral rehydration drink often; small amounts may stay down more easily than a full glass. Once vomiting settles, try plain foods such as rice, bread, soup or bananas, then return gradually to your usual diet. Wash hands with soap and water after using the toilet and before preparing food. Avoid preparing food for other people while unwell, and do not share towels. A pharmacist can advise whether a rehydration product is suitable for you.

Arrange medical advice if you cannot keep fluids down, pass very little urine, feel faint or confused, or have a dry mouth with marked thirst. Seek urgent help for blood in vomit or stools, severe or worsening abdominal pain, a swollen abdomen, a stiff neck, or difficulty breathing. Contact a clinician when symptoms are not settling, return repeatedly, or affect a baby, an older adult, or someone with a long-term illness.

Could a medicine, recent meal, infection or ongoing condition explain these symptoms? What fluid replacement is appropriate for me, and which warning signs should prompt urgent care? If symptoms recur, do I need tests for an underlying bowel or thyroid problem?