Mebendazole: What It Treats and How to Use It Safely

Mebendazole is a widely used antiparasitic that clears common intestinal worms like pinworms, roundworms, hookworms, and whipworms. If you’ve just seen eggs on a tape-test, found a restless child at night, or a stool test confirmed worms, mebendazole is often the go-to choice. It’s on the World Health Organization’s list of essential medicines for good reason: it’s simple, effective, and usually well tolerated.

How mebendazole works

Mebendazole stops worms from absorbing sugar they need to survive. The drug damages the parasite’s energy supply so worms die and pass out of the bowel. It works mainly in the gut — it’s not a systemic drug in typical doses, so side effects tend to be mild for most people. Treatment often clears infection in a few days, though follow-up testing or a repeat dose may be needed for some infections.

Compared with albendazole or ivermectin, mebendazole is preferred for certain worms (like pinworm) in many regions. Albendazole is a close alternative and sometimes chosen for broader coverage; ivermectin is preferred for some parasites outside the gut. Your clinician will pick the best option based on the type of worm and patient factors.

Practical tips: dosing, safety, and buying

Typical adult dosing for pinworm is a single 100 mg tablet, repeated after two weeks if needed. For other worms, doctors may use 100 mg twice daily for three days or other regimens. Never change dose or duration without professional advice.

Side effects are usually mild — stomach pain, diarrhea, headache, or nausea. Serious reactions are rare but call a doctor for rash, trouble breathing, or signs of liver problems (yellowing skin, dark urine). Mebendazole is usually avoided in the first trimester of pregnancy; if you’re pregnant or breastfeeding, discuss alternatives with your provider.

Treating household contacts is often recommended for pinworm because reinfection is common. Wash bedding and clothes in hot water, vacuum carpets, and encourage regular handwashing—especially after using the toilet and before meals.

Buying mebendazole: in some countries it’s over the counter; in others you need a prescription. If you buy online, use a licensed pharmacy with clear contact details and pharmacist access. Avoid sites that sell prescription drugs without asking for a prescription or that offer prices that look too good to be true. Our site has guides on safe online buying if you want more tips.

Before taking mebendazole, tell your clinician about liver disease, pregnancy plans, or other meds you take. If symptoms don’t improve within a week or if you have high fever, severe abdominal pain, or unusual bleeding, get medical help promptly. With the right dose and simple hygiene steps, mebendazole clears many common worm infections quickly and safely.