Complementary medicine: a review of immunomodulatory effects of Chinese herbal medicines.

Popular demand for and scientific interest in complementary or alternative medicine, particularly medicinal botanicals, has increased considerably in recent years. The medicinal botanicals with the longest tradition, and for which extensive data are available, are Chinese herbal medicines and their Japanese counterparts--Kampo medicines. This review focuses on some representative examples of studies examining the effects of some traditional Chinese medicines on various aspects of the immune response. In vitro as well as in vivo studies are cited, the latter including not only animal experiments but also clinical trials. Although by no means exhaustive, this review attempts to show that much research has focused on the specific beneficial effects of Chinese herbal medicines. Studies examining the mechanisms by which they exert their immunomodulatory actions, however, are found much less frequently. Nonetheless, even the limited number of mechanistic experiments presented here reveal that numerous mechanisms are likely involved in the various actions of even a single medicine. It will be the elucidation of such mechanisms that will provide the scientific basis for establishing the efficacy and safety of not only Chinese herbal medicines but all forms of medicinal botanicals.