Plant tissue cultures form the backbone of plant biotechnology, i.e. micropropagation, induction of somaclones, somatic hybridization, and cryopreservation have played an important role. Recently, emphasis has been on genetic transformation, especially for increased production of secondary metabolites by Agrobacterium rhizogenes induced hairy roots. The achievements made are, (1) production of alkaloids, pharmaceutics, nematocidal compounds, and also some novel compounds not found in the whole plant, (2) regeneration of plant resistant to herbicides, diseases, and pests, (3) scale up of cultures in bioreactors, (4) plants with different morphological traits, and (5) transgenic plants for the production of vaccines etc. These developments have far-reaching implications in the improvement of medicinal plants.