Methods of tissue culture and in vitro propagation of medicinal plants, in particular, plants of the genera Hydrastis, Echinacea, Kalanhoe, Thymus and Calendula are described. Methods of genetically engineering the medicinal plants are also described, along with methods of producing recombinant proteins in such plants. Compositions and methods for administering recombinant proteins produced in these plants to subjects in need thereof are provided.
