PRAZIQUANTEL is a new drug that is effective against a broad range of parasitic fluke (Trematoda) and tapeworm (Cestoda) infections. In June 1983, it was approved by the Food and Drug Administration for marketing in the United States. The compound was developed and introduced in the mid-1970s through a joint effort of Bayer AG and E. Merck of West Germany, where the drug is made. Praziquantel is administered orally and is well tolerated; on occasion it causes short-lived side effects of drowsiness, headache, nausea, backache, and abdominal fullness or discomfort. 1,2 Praziquantel is currently labeled in the United States only for schistosomiasis (bilharziasis). It is now the preferred drug for treatment of Schistosoma haematobium and Schistosoma japonicum infections diagnosed in the United States, outmoding the use of metrifonate and niridazole, respectively, because of their more complicated administration or greater toxicity. 3 It is the only drug for treatment of Schistosoma mekongi