Pentachlorosalamide, also known as hydroxychlorosalamide, hydroxychlorosalaniline and hydroxychlorozamide, is the preferred drug for clinical anti worm infection. It has the excellent characteristics of broad spectrum, low toxicity and low residue. As a chemical synthetic drug against worm infection, peclosamide has the excellent characteristics of broad spectrum, low toxicity and low residue. It has a significant effect in the treatment of trematode, tapeworm and other worm infections, and there is no report of drug resistance so far. It is the first choice for clinical anti worm infection.