Levamisole hydrochloride (Levamisole HCl) is an anthelmintic medication used to treat parasitic worm infections, specifically ascariasis and hookworm infections. It is taken orally and works by stimulating the parasitic worm muscles through nicotinic acetylcholine receptor agonism, leading to paralysis. Levamisole has gained prominence among aquarists as an effective treatment for Camallanus roundworm infestations in freshwater tropical fish. It has also been used to treat small ruminant animals. However, levamisole-resistant parasitic worms are common in sheep farms in various countries.