In the medical system (any Allopathy, Ayurveda, Homeopathy, etc.), the emphasis is on medicine. That is you take in the prescribed medicine and that medicine acts on your body system. Your effort is almost nil. But in Yoga, it is you and your efforts that make you disease-free. You perform yoga for a certain time period and see the result.
So, if you can invest efforts in your body, Yoga is for you (along with its countless health benefits). Besides this yoga is also completely free.