Carbon dioxide - the gas that makes drinks fizzy - may help people lose weight.
Injections of carbon dioxide are being used to tackle fat levels in obese people at risk of future health problems.
Researchers believe the jabs will trick the body into a response that results in fatty tissue shrinking, and resulting in reduced waist circumferences.
Carbon dioxide is a natural gas, produced by the cells in our bodies. Non-toxic, it is quickly absorbed into the bloodstream and expelled via our breath and kidneys.
In the treatment, known as carboxytherapy - a fine needle is used to inject carbon dioxide just under the skin.
The procedure takes just a few minutes and is believed to work because the gas diffuses into the surrounding tissues, causing blood vessels to dilate.
Wider vessels mean a stronger blood supply, which brings a rush of oxygen and nutrients to the treated area.
The carbon dioxide kills fat cells, while the extra oxygen eliminates fluid build-up between cells.