Following in vitro infection of an aseptic Catharanthus trichophyllus plant with Agrobacterium rhizogenes (15834), six hairy root cultures were established. These were compared with normal root cultures, derived from the same plant, with respect to production of indole alkaloids. A rapidly growing hairy root line was used for fermenter (201) cultures. The alkaloid content of the roots obtained was examined. Seventeen monomeric indole alkaloids were purified and characterized, including five hitherto undescribed substances. Normal root and hairy root line cultures showed similar alkaloid composition. Analyses, performed at five-week intervals on five-week-old cultures showed variable alkaloid yields. © 1989.