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How the smell of rotten eggs makes men randy

A malodorous gas behind the smell of rotting eggs has been found to play a key role in giving men erections. Scientists believe the discovery could lead to the development of a male impotence drug to rival Viagra.

The whiff of hydrogen sulphide accompanies the biological degradation of sulphur-containing substances. It also belches from the exhausts of cars fitted with catalytic converters.

A study has shown that, prior to sexual intercourse, minute quantities of hydrogen sulphide are released within the key nerve cells of the penis which control the engorgement of the male organ with blood to stiffen it. Scientists believe that the discovery could lead to the development of a new class of drugs to combat erectile dysfunction by affecting a different biochemical pathway to the one targeted by Viagra.

The research was based on experiments performed on the intact erectile tissue of eight men who had undergone sex-change surgery in a hospital in Italy.

"We found that hydrogen sulphide is involved in human penile erection. That was proved in this study," said Professor Giuseppe Cirino, of the University of Naples Federico II.

About one third of men with erectile dysfunction do not respond to Viagra, and it is those men that Professor Cirino said may benefit from the development of a drug targeted at hydrogen sulphide rather than nitric oxide.