PIP: Significant advances have occurred over the past 20 years in the drugs available to treat parasitic helminths. Safe, effective, inexpensive, single-dose treatments are now available for most of the common species of worms. This article reviews the main drugs used against the four major groups of worms found in Africa: intestinal worms, tapeworms, schistosomes, and filarial and tissue nematodes. Three drugs--praziquantel, ivermectin, and a benzimidazole such as albendazole or mebendazole--treat a broad range of common, debilitating helminths that occur in Africa, often in the same people. After clinical trials, the World Health Organization has endorsed concomitant use of praziquantel and albendazole to treat intestinal worms and schistosomiasis. Mass treatment with anthelmintics is becoming widespread in areas with a high prevalence of disease. Schoolchildren are an especially appropriate, cost-effective target for mass treatment. Treating children has been shown to reduce transmission to untreated members of the community.