Fainting on the toilet: causes and what to do

The body can respond to bowel movements or urination by slowing the heart and widening blood vessels. Straining, abdominal pain, diarrhoea, vomiting, heat or prolonged sitting may make the change more noticeable. Anaemia, low blood sugar, dehydration and heart-rhythm problems are other possibilities; one episode does not establish the cause.

If you feel faint, stop straining and lower yourself to the floor, preferably on your back with your legs raised. Turn on your side if you vomit. Keep the bathroom door unlocked and call for help. Once fully awake, drink small amounts of fluid if safe, and rise slowly with support. Check for head injuries after a fall.

Get urgent help for chest pain, breathing difficulty, severe abdominal pain, black or bloody stool, heavy bleeding, a serious injury, seizure-like movements, prolonged confusion or an irregular heartbeat. Arrange prompt medical review after a first episode, an episode without warning, or any recurrence.

Tell the clinician whether you were urinating or opening your bowels, straining, in pain, dehydrated or taking new medicines. Ask whether blood pressure checks, an ECG or blood tests are appropriate, and how to reduce bathroom falls.