Digitonin is a steroidal saponin (saraponin) obtained from the foxglove plant Digitalis purpurea. As a non-ionic detergent Digitonin is commonly used to solubilize membrane-bound proteins. Digitonin forms a complex with its lipophilic terpenoid moiety with cholesterol in the biomembrane; additionally it binds to glycoproteins and glycolipids of the cell membrane with its sugar side chain. This leads to a severe tension of the biomembrane and influences membrane permeability. Digitonin, in combination with secondary metabolites, leads to a stronger inhibition of ABC transporters as when applied alone. Digitonin is used as a clinical reagent for the cholesterol determination. Digitonin mixed in the diet was well tolerated by rats and cynomolgus monkeys (Macaca fascicularis), and prevented the expected rise in plasma cholesterol in monkeys fed a diet containing butter and cholesterol.