According to Boston University and published in the Journal of the American Medical Association, holistic medicine sold on the internet may contain high levels of mercury, lead, and arsenic.
A big concern is something called "Ayurvedic Medicine" which is an Indian practice that mixes herbs with minerals and metals. After studying almost 200 Ayurvedic products from 37 manufacturers, researchers found that one in five contained exceedingly high levels of lead, mercury, and arsenic and most of the products were made in the U.S.
The study is calling on government agencies to change the way supplements are regulated in the United States. As of now, daily dose limits for metals are not mandated.