The FDA said that, following a consumer complaint, the FDA determined that the product contains sulfoaildenafil, which is a chemical similar to sildenafil, the active ingredient in Viagra.
Sulfoaildenafil may interact with prescription drugs known as nitrates, including nitroglycerin and cause dangerously low blood pressure, the FDA said.
The product is distributed on the web through numerous sites, as well as StiffNights.com, and at retail stores by Impulsaria LLC of Grand Rapids, Mich.
It is sold in bottles containing 6, 12 or 30 red capsules or in blister packs, containing one or two capsules.
"Because this product is labeled as an all-natural dietary supplement, consumers may assume it is harmless and poses no health risk," FDA spokeswoman Deborah M. Autor said. "In fact, this product is illegally marketed and can cause serious complications."