Any form of medicine or healing that does not fall under conventional medical practise is referred to as "alternative medicine." The term "alternative medicine" refers to a variety of medical practises and systems from all over the world. The word "alternative medicine" has a wide range of meanings. While doctors in one region of the world may consider a practise to be mainstream, doctors in another part of the world may consider it to be alternative. Alternative medicine has been practised for hundreds, if not thousands, of years. Others are rather new. Due to sufficient evidence that it works and poses no hazards, something that began as a "alternative" treatment might sometimes become part of mainstream medicine.