Anyone thinking of volunteering for a medical trial — despite the disastrous drugs tests which recently left six men critically ill at Northwick Park Hospital in North London — might feel justified in asking the organisers a simple question: have you tried this on yourselves? The answer, almost invariably, will be no. In most cases, the idea of doctors or researchers using themselves as the subjects of their own experiments is frowned on if not rejected. Yet many of the most remarkable advances in medicine have resulted directly from self-experiments by maverick medics flouting accepted ethics. And there are even doctors today who argue that more of their colleagues should be first to take a spoonful of their own medicine.

Professor John Saunders, who chairs the ethical issues committee of the Royal College of Physicians, certainly believes that there are circumstances in which doctors should be volunteers in their own trials. Having been a subject in his own research in the past, he says: “I think it is perfectly legitimate for people to say: ‘If you aren’t prepared to undergo this experiment on yourself, how dare you expect others to do so’. ”

The stringent regulatory system governing medical research would normally preclude doctors taking part in their own trials. But this has not stopped many researchers from becoming their own guinea pigs in recent years.

Probably the most spectacular example is Barry Marshall, the Australian gastroenterologist who proved his theory that most stomach ulcers are caused by the common bacteria Helicobacter pylori by drinking a mixture containing the bug in 1982.

The familiar symptoms of gastritis appeared within days. Professor Marshall and his colleague, Robin Warren, shared the Nobel Prize for Medicine last year in recognition of their discovery, which transformed a chronic condition, previously thought to be caused by stress and treated with surgery or life-long medication, into an easily treatable complaint that can be eradicated with a short course of antibiotics.

Recent self-experimenters have included Pradeep Seth, an Indian microbiologist who injected himself in 2003 with a potential vaccine he had developed for HIV. While it had been tested on animals, the vaccine had not been cleared for human trials. Although his action, which had no adverse effects, was condemned by colleagues, Seth has no regrets. “There is always a place for self-experiment in science,” he says.

Whether foolhardy or selfless, researchers such as Marshall and Seth have been inspired by a long line of medical pioneers who have offered themselves first in the cause of scientific progress. Many look back to John Hunter, an 18th-century surgeon and anatomist who put himself through a series of highly risky experiments, including taking various strengths of poison. Most controversially, he is believed to have given himself gonorrhoea — applying the pus of an infected patient to his own penis — to test his theory that it would develop into syphilis. The three-year experiment is thought to have forced him to postpone his marriage. Although ultimately flawed, since the pus he used contained syphilis and gonorrhoea and the trial erroneously suggested that the two were the same disease, his self-experiment was later repeated by medical students in Edinburgh to produce the correct results.

Even today, however, there are doctors who deny that Hunter experimented on himself in the apparent belief that it was more honourable for him to have given a third party venereal disease than to have given it to himself.

Equally reckless, if somewhat more successful, were the 19th-century pioneers of anaesthesia for whom self-experimenting seemed almost compulsory. The young chemist Humphry Davy discovered the properties of nitrous oxide, or laughing gas, after inhaling it with friends, including the poets Robert Southey and Samuel Coleridge. Although he became hopelessly addicted, Davy never put his discovery into practical use.

That was left to Horace Wells, an American dentist who was fascinated by demonstrations of laughing gas at travelling fairs in the 1840s.Observing that those who inhaled the gas felt no pain when they banged their shins on returning to their seats, Wells offered himself as a volunteer while a colleague extracted a troublesome tooth. Although he used the gas successfully on his own patients, Wells became frustrated at the lack of support from his peers and — by this time addicted to chloroform — took his own life. William Morton, a fellow US dentist, took up the anaesthesia baton, testing ether, at first on himself, naturally, and then in an acclaimed operation to remove a patient’s neck tumour in 1846.

The crusade to find new and better anaesthetics continued with the Scottish obstetrician Sir James Young Simpson, who tested chloroform on himself and two assistants in 1847. All three were discovered unconscious under a table. After dramatic successes on patients, the anaesthetic won royal approval when Queen Victoria enjoyed a pain-free childbirth with the aid of chloroform in 1853.

Further advances are equally owed to selfexperimentation. The American surgeons William Halsted and Richard Hall discovered the benefits — and disadvantages — of morphine and cocaine after their self-testing led to chronic addiction. Even the first use of spinal anaesthesia, at the end of the 19th century, was pioneered by two German doctors, August Bier and August Hildebrandt, who tested it on each other.

It is only because of such intrepid acts, says Professor David Hatch, the professional standards adviser at the Royal College of Anaesthetists, that pain-free surgery became possible. “It was probably the most amazing discovery of its century, if not of all time,” he says.