Given the relatively low cost of yoga programs, yoga could easily be implemented worldwide as a preventive and therapeutic means to improve health, well-being, and, for patients with chronic health conditions, better symptom management. As such, healthcare providers are increasingly presented with patients using, or interested in trying, yoga for the management of their medical conditions. This increased use of yoga raises the issue of the efficacy and safety of yoga as a health therapy. Moreover, psychological and physiological mechanisms of action of yoga as a preventive and therapeutic remain largely unknown. Both efficacy and mechanisms need to be investigated in more depth in order to improve both clinical decision-making and research quality on one of the most prevalent complementary therapies used for the prevention and management of chronic health conditions. This review paper is a synthesis of other research works done in the field of yoga and its effect on our different human systems which has been discussed in details below.