The gas responsible for the foul odour of flatulence and rotten eggs may play an important role in regulating blood pressure, Canadian researchers say in a study released Friday.

Hydrogen sulphide — a toxic gas that, among other things, is made by bacteria living in the human intestinal tract — relaxes blood vessels and allows for easier blood flow, according to the study in Friday's edition of the journal Science.

It is hard "not to overestimate the biological importance of hydrogen sulphide or its implications in hypertension," writes Rui Wang, a physiologist at Lakehead University in Thunder Bay, Ont. Wang co-authored the study with Lingyun Wu, a pharmacologist of the University of Saskatchewan and other researchers from the Johns Hopkins medical school in Baltimore.

The five-year mouse study found that an enzyme called CSE produced the gas in cells lining the walls of blood vessels throughout the body.

That finding confirmed earlier research that suggested a link between the enzyme and the gas.

In the study, researchers bred mice with lower-than-average levels of CSE and found that the engineered animals had significantly depleted levels of hydrogen sulphide compared to a group with normal levels of the enzyme.

The researchers also found that the mice with CSE deficiencies had blood pressure levels that were 20 per cent higher than the normal mice.

However, when the mice bred for lower CSE levels were given methacholine, a drug given to relax blood vessels, their blood pressure levels were not significantly different than those with normal levels of the enzyme. The researchers said this suggests the gas is responsible for the change in blood pressure.

The findings could lead to new treatments for high blood pressure in humans, said the study authors.

"Now that we know hydrogen sulphide's role in regulating blood pressure, it may be possible to design drug therapies that enhance its formation as an alternative to the current methods of treatment for hypertension," study co-author Dr. Solomon H. Snyder, a neuroscientist at Johns Hopkins University, said in a Johns Hopkins news release.