Bisacodyl: Uses, Side Effects and Precautions

Bisacodyl is a stimulant laxative used for constipation. Stimulant laxatives speed up bowel movements and usually work in 6 to 12 hours. Read our guide to high-fibre foods for constipation for steps to try first.

What are the common side effects?

Feeling sick, diarrhoea, and stomach pain or cramps can occur. If you get diarrhoea, stop taking it and drink plenty of fluids. If you get cramps, reduce the dose or stop until the pain passes.

Can it affect the contraceptive pill?

Severe diarrhoea for more than 24 hours may stop the pill from protecting you. Check the pill packet or ask your pharmacist.

When should I get help?

Contact a doctor straight away for dizziness, blood in your stools or vomiting. Call triple zero (000) for sudden swelling of the lips, mouth, throat or tongue, trouble breathing, or fainting. See our constipation guide for other warning signs.

Doses vary, so follow your prescriber, pharmacist and the medicine label. In an emergency, call triple zero (000). For a possible overdose, call the Poisons Information Centre on 13 11 26.

Source: NHS: Side effects of bisacodyl and Healthdirect: Constipation. General education does not replace individual medical advice. Updated November 2026.

Explore our health guides.