Herbal viagra is a name that can be given to any herbal product advertised as treating erectile dysfunction.[1] The name Herbal viagra is taken from the brand name Viagra, the name under which drug company Pfizer sells Sildenafil citrate, a drug that is used to treat erectile dysfunction.[2] There are many different products being advertised as herbal viagra, all being made with different ingredients. One product, Duro is known to contain an extract of fungus extracted from the larval remains of silkworms. Duro is also said to benefit sportsmen and women through increased stamina.[3] Many of these herbal remedies originate from ancient tribes, such as Mapuche Viagra which is used by Chile's Mapuche people.[4] Herbal viagras, contrary to what the name suggests, do not normally contain Sildenafil Citrate. Viagra has become a generic term for many people discussing drugs designed to treat erectile disfunction.[5] Herbal viagras often carry a number of dangerous side effects, primarily they often cause abnormally low blood pressure and can restrict blood flow to vital organs. There is also evidence to suggest some preparations may be toxic if taken in larger doses.[1] Herbal viagra is predominantly sold through the internet, and in 2003, around 4% or 1 in 25 of all e-mail messages sent offered herbal viagra, genuine pharmaceuticals and other herbal remedies.