There are several medicines that can be used to treat worm infections in humans. The most commonly prescribed medicine for threadworms in the UK is mebendazole, which is also used to treat roundworm, whipworm, and hookworm infections. Mebendazole works by stopping worms from using sugar (glucose) to live, which kills the worms. It is available as chewable tablets or a liquid that can be swallowed, and it can be bought over the counter from a pharmacy for adults and children aged 2 years and over. It is also available on prescription for children aged 6 months and over.

Other medicines that may be prescribed for various types of worm infections include albendazole, levamisole, niclosamide, praziquantel, diethylcarbamazine, ivermectin, and tiabendazole. These medicines are not licensed for use in the UK and are specially imported to treat more unusual worm infections. They are usually prescribed by doctors who specialize in treating worm infections.

It is important to note that when taking mebendazole, it may take several days to kill all the worms, and a second dose may be needed after 2 weeks. Mebendazole kills worms but not their eggs, so it is important to have good personal hygiene to help stop the worms from coming back. The most common side effect of mebendazole is stomach pain.