Diarrhoea like water: what it can mean and what to do

Very loose stools contain more water than usual because the bowel is moving contents quickly or is not absorbing fluid effectively. A stomach infection, food poisoning, a food intolerance, or a medicine can trigger it. Persistent or repeated episodes may also occur with conditions such as gastroenteritis, giardiasis, coeliac disease, Crohn's disease, irritable bowel syndrome, or an overactive thyroid. The symptom alone cannot identify the cause.

Take frequent small sips of water and use an oral rehydration solution if losses are substantial; its balance of water and salts helps replace what the stool removes. Continue light foods when able, such as rice, bread, soup, or bananas. Avoid alcohol, very fatty meals, and drinks that worsen symptoms. Wash hands with soap and water, avoid preparing food for others, and rest. Do not start antibiotics without clinical advice.

Seek urgent medical help for fainting, confusion, severe weakness, inability to keep fluids down, very little urine, severe or worsening abdominal pain, blood or black stool, or a high fever. Arrange medical assessment when watery diarrhoea is not settling, keeps returning, follows recent travel or antibiotics, or affects an older adult, a pregnant person, or someone with a long-term illness. Dehydration can develop before thirst feels strong.

Ask which cause fits your pattern, whether you need stool testing, and which drinks or medicines are suitable alongside your regular treatments. Mention travel, new foods, recent antibiotics, fever, pain, blood, and how often you are passing stool.