 Preventive chemotherapy PC programs in which single-dose albendazole 400 mg or single-dose mebendazole 500 mg - the drugs of choice for STH - are administered at the population level, is the main strategy for STH control. To ensure quality, these drugs are being widely donated by GlaxoSmithKline GSK albendazole ALB, Zentel and Johnson Johnson mebendazole MEB, Vermox. In addition to this, there are a wide variety of ALB and MEB tablets available on the local market. Although little is known about the quality of anthelmintics sold for human use, several publications have reported variability in the quality of generic anthelmintics used in veterinary medicine. The concentrations of nine anthelmintic products levamisol and MEB purchased in pharmacies and from agricultural merchants in Kenya varied from 0 to 118 of their claimed composition Monteiro et al., 1998. Efficacy studies of seven brands of ALB against gastrointestinal nematodes in sheep in Ethiopia showed that the efficacy of only five of the seven brands was satisfactory Kumsa et al., 2010. 