An object of the present invention is to provide a novel antischistosomal agent, and more specifically, to provide a novel drug capable of inhibiting a growth of schistosomes in vivo to prevent development of liver dysfunction due to eggs of the schistosomes in the case of infection with the schistosomes. The novel antischistosomal agent includes as an active ingredient a peroxide derivative. Specifically, the novel antischistosomal agent includes as an active ingredient a peroxide derivative represented by the general formula (I): where C represents an alicyclic hydrocarbon ring group which may be substituted, and n represents an integer of 1 to 6.