A vital poison.

In 1992 a woman lay unconscious at St George's Hospital in London, dying of toxic shock syndrome. Her life was saved by by pioneering treatment with nitric oxide. "A Vital Poison" is the story of the discovery that our bodies need a poisonous gas, nitric oxide (NO), in order to function. Nitric oxide is a vital factor in blood pressure control, in defence against cancer cells and is a mediator of memory in the brain. Impairment of nitric oxide production can result in such conditions as toxic shock syndrome, blue baby syndrome, impotence, hypertension, atheroclerosis, epilepsy, diabetes, even multiple sclerosis. Yet, until a few years ago, it was known only as a pollutant produced by cigarette smoke and vehicle exhaust.