Dewormers, also called anthelmintics, are drugs that repel or kill intestinal worms. Commonly, mebendazole is a broad-spectrum dewormer, which is effective against roundworms and hookworms. Albendazole is a highly effective and low-toxic broad-spectrum anthelmintic that is more effective against mixed infections of nematodes. Levamisole has a killing effect on nematodes, thiacil is a broad-spectrum anthelmintic, as well as clonidine has a killing effect on tapeworms and adult worms, and finally praziquantel is the drug of choice for the treatment of various tapeworm diseases.