The venom of the black scorpion, Androctonus mauretanicus mauretanicus, was obtained by means of manual stimulation and was analyzed using high-performance liquid chromatography. Starting from 20 mg of venom and using only two chromatographic steps, six toxins were purified to homogeneity. They have been characterized by their amino acid content and compared to those already isolated from a pool of venoms obtained using electric stimulation (Rosso and Rochat, Toxicon 23, 113-125, 1985). The toxins Amm I and Amm II were not found, suggesting either different levels of toxin expression or the existence of Androctonus mauretanicus mauretanicus subspecies. Using rat brain synaptosomes, it was demonstrated that the toxins Amm III, Amm IV and Amm V were alpha-toxins. The toxin Amm VI was neither alpha- or beta-toxin. Unexpectedly, the toxin Amm VII was found to be a beta-toxin, the first one identified in a north African scorpion venom. In addition, some toxins active on mammals exhibited different levels of specificity towards phylogenetically related groups of arthropods.