Abstract: The invention concerns a new pharmaceutical agent for oral or topical administration in the treatment of protozoal diseases, in particular of leishmaniasis, which contains as the active substance one or several compounds having the general formula I in which R1 is a saturated or monounsaturated or polyunsaturated hydrocarbon residue with 12 to 20 C atoms and R2, R3 and R4 denote independently of one another hydrogen, a C1-C5 alkyl group, a C3-C6 cycloalkyl group or a C1-C5 hydroxyalkyl group whereby two of the residues R2, R3 and R4 can together form a C2-C5 alkylene group which, if desired, can be substituted with an —O—, —S— or NR5 group, in which R5 is hydrogen, a C1-C5 alkyl group, a C3-C6 cycloalkyl group or a C1-C5 hydroxyalkyl group as well as, if desired the usual pharmaceutical auxiliary, diluting, carrier or/and filling substances.