Just last week, the government advised consumers to stop using herbal remedies that contain Aristolochia, also known as Virginia snakeroot.

Along the way, he experimented with 14 kinds of snakeroot before discovering that the real thing, Virginia snakeroot (Aristolochia serpentaria), could cause cancer and renal failure.

Dr. Kessler said he had bought a bottle of Aristolochia capsules, sold as "Virginia Snakeroot," from an American supplier via the Internet.

The species is commonly known as Virginia snakeroot and is native to eastern North America, from Connecticut to southern Michigan and south to Texas and Florida.

Virginia snakeroot is considered an endangered species in New York, where no reports of the species were made for the century between 1895 and 1994, when it was rediscovered in the Hudson Highlands.

A. serpentaria (Virginia snakeroot) is thus named because the root was used to treat snakebite, as "so offensive to these reptiles, that they not only avoid the places where it grows, but even flee from the traveler who carries a piece of it in his hand".

Virginia snake root (Aristolochia serpentaria)

Along the way, he experimented with 14 kinds of snakeroot before discovering that the real thing, Virginia snakeroot (Aristolochia serpentaria), could cause cancer and renal failure.