When you wince at the smell of a stink bomb, sewage or rotten eggs, hydrogen sulfide is slipping into your nostrils.

Now, researchers from England say the gas has a role in regulating blood pressure.

Gases are normal in the blood, and it has been thought that imbalance between them can cause problems. The researchers said that a drop in nitric oxide, for example, can increase blood pressure. Hydrogen sulfide may fight the effect.

H2S, as it is also known, relaxes arteries and veins, allowing for a smoother blood flow.

The researchers also found a way to make a new molecule that lets H2S get into the blood in a controlled manner, rather than breathing it from a canister, as was done in the past.