Niclosamide is an anti-intestinal worm drug with the chemical formula C13H8Cl2N2O4 Molecular weight 327.119 CAS number 50-65-7 Light yellow crystalline powder, easy to turn yellow in the air. Niclosamide is an eelicide (Iampricide) and a molluscicide (molluscicide). It is a salicylamide derivative. Its anti-insect mechanism is to inhibit the mitochondrial oxidative phosphorylation process in the cells of the insect body. The reduction of ATP production makes the tapeworm's head and adjacent segments deteriorate, and the worms fall off the intestinal wall and are excreted in feces. Not effective against eggs [1]. Death knot tablets are easily digested and decomposed by proteases in the intestinal lumen, releasing eggs, which may cause cysticercosis [1]. It also kills snails and cercariae of Schistosoma japonicum. It can kill many kinds of snails, beef tapeworms (Taenia saginata), pork tapeworms (Taeniasolium), fish tapeworms Schizophaga latifolia, short hymenocysts tapeworms, and cercariae (Cercariae). In agriculture, it is mainly used to kill snails (also known as large bottle snails, apple snails, Pomacea canaliculata in English) in rice fields. At the same time, in public health control, it is used to kill Oncomelania (the intermediate host of schistosome). Niclosamide can rapidly produce metabolic changes in the water, and the action time is not long. It is also used in commercial fish farms to kill and remove unwanted fish before the fish is replaced with new water. Niclosamide is very toxic to fish, but has only a short half-life in the water. Use this killer It only takes a few days after the fish preparation to add new fish.