WOULD-BE holidaymakers desperate to avoid an unsightly cold sore are helping to send sales of a new gadget soaring.

Gordon Dougal, a GP in Easington, east Durham, and Darlington surgeon Jim Haslam have sold more than 16,000 of their Virulite treatment units since launching their invention in 2001.

But in recent months they have seen a growing trend for punters to buy the £45 gadgets before going on holiday.

The hand-held Virulite unit emits harmless infrared light to stimulate the body's immune system, resulting in cold sores clearing more quickly.

The inventors say the best time to use the machine is when patients feel a tell-tale "tickle" as a cold sore develops.

"We sell lots of Virulite machines to people going on holiday who are desperate to stop a cold sore developing," said Dr Haslam, who also works as an eye surgeon at Darlington Memorial Hospital.

The doctors already have hard scientific evidence showing that exposing white blood cells to infrared light with a wavelength of 1,072 nanocycles has a positive effect on tissue.

They believe this is the mechanism that prevents cold sores from developing.

Small-scale clinical trials have shown that Virulite works three times as fast as cold sore creams.

Now the two medics want a much larger trial to gather more evidence.

"We are looking for recruits for a new cold sore trial. We need 120 people, who must be over 18 and prone to recurrent cold sores," said Dr Haslam.

The doctors say they have had very good feedback from customers.

"People tell us they used it once and then didn't need to use it again," Dr Haslam added.

Virulite machines are now being manufactured in China.

From small beginnings, the inventors now have their own company - Virulite Distribution Ltd - and an office in Newton Aycliffe, County Durham.

Apart from sales of Virulite, the pair have also been marketing Restorelite, a separate gadget which uses the same scientific principle to iron out wrinkles. So far, they have sold more than 3,000 Restorelite units at £199 a time.

* To volunteer for the trial or for more information, call 0800 052 3939 or visit www.vcs.eu.com