The 2-alkylpyrrolidine R-bgugaine, a natural alkaloid isolated from tubers of Arisarum vulgare Targ. Tozz. (Araceae), and its isomer S-bgugaine, obtained by an asymmetric synthesis, were examined for their cytotoxic activities on two cancerous cellular lines: the murine mastocytoma cell line P815 and the human laryngeal carcinoma cell line Hep. These two alkaloids exhibited an important cytotoxic activity on these two cancerous cellular lines. The concentrations required to induce 50% of lysis (IC(50)) for R-bgugaine and S-bgugaine alkaloids were determined, and are 10 and 5 microg mL(-1), and 5 and 100 microg mL(-1), respectively, for the mastocytoma P815 and carcinoma Hep, compared with those of Adriamycine (5 microg mL(-1) for P815 cell line and 5 microg mL(-1) for Hep cell line), taken as positive controls.