6-Phosphogluconate dehydrogenase is a potential target for new drugs against African trypanosomiasis. Phosphorylated aldonic acids are strong inhibitors of 6-phosphogluconate dehydrogenase, and 4-phospho-d-erythro-nate (4PE) and 4-phospho-d-erythronohydroxamate are two of the stron-gest inhibitors of theTrypanosoma bruceienzyme.