Alternative medicine includes practices like Ayurveda, Siddha, Unani, Homeopathy, Naturopathy, and Yoga that are not considered part of conventional medicine. These practices focus on treating the whole person and use natural therapies to boost health and reduce symptoms. While alternative medicines have fewer side effects than conventional treatments and can lower costs, more scientific research is still needed to prove their effectiveness for certain conditions. The document then provides details on the principles and therapies used in various alternative medicine systems practiced in India.