There's no cure for the common cold - or is there?

A honey farm in North Yorkshire may have a surprising answer to this age-old conundrum.

For the industrious bee has become a major player in the health industry - thanks partly to a Thirsk venture, which has helped put a substance called propolis on the sector's map.

Propolis is collected by bees from buds and trees, which is blended with wax flakes secreted from glands on their abdomens.

The natural antiseptic substance, which is pliable and sticky when warm, is then used by bees to line the interior cells of hives, creating an area protected from outside environments, in preparation for the queen's egg laying.

With humans it can be equally useful, acting as a remedy for eczema, sore throats, the treatment of burns - and also for the common cold.

Mike Spencer, manager of Bee Health honey farm in Thirsk, said: "We have thousands of customers who say they have been taking propolis for more than ten years, and haven't had a cold since."

Claire Atkinson, supervisor at Holland And Barrett, York, said: "Customers say it works quite well and we do sell quite a lot of it.

"We get repeat customers for all the propolis products, one of the good sellers for the cold.

"I've used the propolis lozenges and they worked very well - they help you to swallow and breathe more easily."

A saleswoman at the Nut Centre health shop in York said: "Customers come back and have given us very positive feedback.

"Everybody who has used it has said it's really effective, particularly the lozenges and throat sprays."

Bee Health honey farm started selling propolis 16 years ago as a small, locally-based enterprise.

In 1994 it won Yorkshire Television's Business Enterprise Of The Year.

Since then the business has expanded, employing more than 100 people, and supplying propolis to natural medicine giants such as Holland And Barrett.

Bee Health started processing propolis in 1991.

Mr Spencer said: "Back then it was relatively unknown - only a few health shops sold it, but after we won the business enterprise award in 1994 the demand for the substance became excessive, not only from the general public but also from health shops all over country.

"People were going in asking for propolis."

What is propolis?

Propolis means "defender of the city" in Greek.

Bees use propolis to protect their "city" by narrowing the entrance to prevent the entry of unwanted intruders, in much the same way as humans use it to ward off bugs.

Ancient Greek texts refer to propolis as a cure for infections and diseases.

The substance is also believed to reduce plaque formation on teeth.