Chinese herbal medicine. Bottles (blue caps) of a Chinese herbal energy drink containing the herbs astragalus (Astragalus membranaceus) and ginseng (Panax sp.) in royal jelly. Royal jelly, secreted from the salivary glands of worker bees (Apis sp.) as food for bee larvae that may develop into queen bees, contains essential amino acids, vitamins and minerals. Chinese medicine is based on the theory of a universal life force called Qi that is balanced in the body by the complementary forces yin and yang. Disorders are caused by an imbalance of yin and yang. Herbal remedies are prescribed to restore the balance. Photographed in London, UK.