Avermectin is a class of medications derived from the soil bacterium Streptomyces avermitilis. It is primarily used as an antiparasitic agent, effective against a variety of parasites in both humans and animals. Avermectin works by disrupting the nervous system of the parasites, leading to their paralysis and death. One of the most well-known derivatives of avermectin is ivermectin, which is widely used to treat conditions like river blindness and lymphatic filariasis. Avermectin and its derivatives have also found applications in veterinary medicine, helping to control parasitic infections in livestock and pets.