<jats:title>Abstract</jats:title><jats:p><jats:italic>Catharanthus roseus</jats:italic> cells suspended in production medium showed the presence of four <jats:italic>Aspidosperma</jats:italic>‐type alkaloids, however, no vindoline. Cells grown in media with the pH adjusted to 7.0 produced 3.3 mg total alkaloids/g dry weight. At pH 5.0, 1.7 mg of alkaloid/g dry weight was produced. (<jats:italic>S</jats:italic>)‐Adenosyl‐methionine did not stimulate the production of vindoline. When added to cell suspensions for 21 days, vindoline and catharanthine were degraded to non‐alkaloidal substances, not dimerized to bisindole alkaloids.