Cultured Papaver bracteatum cells accumulate large amounts of dopamine (0.1-4 mg/g fresh wt.) and much lower levels of the alkaloids, thebaine (0-6 μg/g fresh wt.) and sanguinarine (10-500 μg/g fresh wt.). Upon removal of hormone from their culture media, organogenesis and an elevation in morphinan alkaloid concentration were observed. Light and electron microscopic studies reveal that a correlation exists between the appearance of laticifer-like cells and thebaine in these cells.