A new warning from FDA over an ingredient commonly found in dietary supplements.
The stimulant is known as DMAA or dimethylamylamine.
It's promoted as a natural way to enhance athletic performance and speed up weight loss.
The agency says DMAA can cause increased blood pressure, shortness of breath, chest tightening, cardiovascular problems and even heart attacks.
The FDA has received reports of 86 illnesses and deaths associated with products containing DMAA.