This article is for general information only and is not medical advice. If you think you have an infection, speak to a pharmacist or your GP.
The short answer
No. Laxatives help you empty your bowels, but they do not kill worms or other parasites, and there is no good evidence that they clear an infection. If you think you have worms, the NHS advice is to see a pharmacist or GP. The proven treatments are simple and usually take days, not weeks.
What laxatives actually do
Laxatives are a treatment for constipation. The NHS describes four main types:
- Bulk-forming laxatives, such as ispaghula husk, which increase the bulk of your poo so it is easier to pass.
- Osmotic laxatives, such as lactulose and macrogol, which draw water into the bowel to soften poo.
- Stimulant laxatives, such as senna and bisacodyl, which stimulate the muscles that line your gut.
- Poo-softener laxatives, which let water into poo to soften it.
None of these act on parasites themselves.
Why a laxative will not clear parasites
Gut parasites are well adapted to staying where they are. Tapeworms and hookworms attach themselves to the wall of the intestine. Threadworms lay eggs around the bottom, and those eggs are easily swallowed again, which keeps the infection going. Giardia is a microscopic parasite that lives on the lining of the small intestine.
Emptying the bowel faster does not remove any of these. Giardiasis is a good example: its main symptom is diarrhoea, yet the infection carries on until it is treated.
Where the idea comes from
Some older worm medicines combined an anti-worm drug with a laxative such as senna, to help flush worms out after the medicine had dealt with them. The laxative was never the part that treated the infection. Today the NHS advises mebendazole for threadworms, which you can buy from a pharmacy, together with strict hygiene.
The risks of using laxatives this way
The NHS says laxatives should ideally only be taken occasionally, and for up to a week at a time. Common side effects include bloating, farting, tummy cramps, feeling sick and dehydration.
Using laxatives too often or for too long can cause:
- diarrhoea
- the bowel becoming blocked by large, dry poo
- unbalanced salts and minerals in your body
That last point matters. Repeated diarrhoea means losing fluid along with minerals such as potassium, sodium and magnesium. To see how those minerals work together, try our free Mineral Interaction Wheel.
What actually treats a parasite infection
- Threadworms. A pharmacist can recommend mebendazole. Everyone in the household aged 2 and over should be treated, even if they have no symptoms, alongside 2 weeks of strict hygiene. Mebendazole is not recommended in pregnancy, while breastfeeding or for children under 2, so speak to a pharmacist, midwife or GP. See the NHS threadworms page.
- Other worms, such as roundworm, hookworm and tapeworm. A GP may ask for a poo sample and will prescribe medicine that you take for 1 to 3 days. See the NHS page on worms in humans.
- Giardiasis. This is diagnosed from a poo sample and treated with antibiotics. Symptoms usually stop within about a week. See the NHS giardiasis page.
When to see a pharmacist or GP
See a pharmacist if you have small white worms in your poo that look like pieces of thread, or extreme itching around your bottom, particularly at night.
See a GP if you:
- find a large worm, a piece of worm or worm eggs in your poo
- have a red, itchy, worm-shaped rash on your skin
- have sickness, diarrhoea or a stomach ache for longer than 2 weeks
- are losing weight for no reason
Tell the GP if you have been abroad in the last 2 years.
Related reading
- How long does it take to get rid of parasites?
- Clove, black walnut hull and wormwood: what the research says