Ayurveda is an alternative medicine to what?

Ayurveda… …is the traditional medicine practiced in india; it is considered an alternative medicine to western allopathic/osteopathic medicine, which arose from greek & european traditions.
"Alternative" In general, "alternative" medicine is called that because most of it is deemed outside the range of conventional training. So it is "alternative" to conventional treatment. Ayurveda, classical homeopathy, acupuncture, chiropractic, energy medicine such as reiki, functional medicine, etc, are some of the systems seen as "alternative." interest in these approaches is growing anyway!
Proven vs unproven. By definition, "alternative" is different than modern western medicine. Generally any drug, herb, treatment, or procedure that stands up to rigorous scientific scrutiny is included in modern medicine. The problem is that many alternative practices, herbs etc do not stand up to scientific scrutiny and cannot be shown to work. They therefore remain "alternative". Be careful and watch your wallet.