Malethamer is the generic name of a new synthetic hydrocarbon copolymer with extraordinary water-binding properties, being able to absorb 200 times its weight of water. It is physically and chemically binds poliovirus 1 and certain bacterial enterotoxins. Ethylene-maleic anhydride copolymers and their derivatives have come to be considered for a number of applications generally involving the formation of insoluble complexes with proteins and viruses. The copolymer is not absorbed from the gastrointestinal tract and is pharmacologically inert. Malethamer, because of its water absorbing quality, is an effective compound for the symptomatic control of diarrhea, both organic and functional.