Jingzhi Kesou Tan Chuan Wan, is the name of a drug imported from China, that contains a carcinogen, and could cause death.  This unlicensed herbal product was distributed widely and 900 packs are still unaccounted for after a recall operation by the Importer.  Anyone who has taken it is advised to see their doctor immediately.   Aristolochia is the ingredient that can cause cancer and even death.  It is dangerous.  This very real danger should serve as a warning to anyone tempted to take unknown herbal products for conditions such as impotence or anything else that should involve a trip to a doctor,  that cheap may just be lethal at worst or cause severe problems.  If you need Viagra don't be tempted by some cheap substitute, as it may kill you.