Researchers have confirmed what parents have found out through hard experience: that removing headlice from their young children is often easier said than done.

But, according to today's British Medical Journal, fine-combing and conditioning wet hair may be a better way of beating the bugs than using over-the-counter chemical treatments.

The old-fashioned method is outdoing insecticides as the lice become increasingly resistant to the treatments that once dislodged them. A trial led by researchers at the London School of Hygiene and Tropical Medicine revealed a success rate of only one in seven for chemicals.

The study looked at 56 children treated using the combing technique in the Bug Buster kit, developed by the charity Community Hygiene Concern, and 70 who had chemicals applied. A check for lice was done two to four days after the end of both treatments. Combing removed infestation in 57% of the first group of children, four times better than the chemicals.

"Millions of pounds are spent each year by parents or through NHS prescriptions on lice treatments and many seem to be virtually useless," said Nigel Hill, who led the study.

Dr Hill said chemicals were effective initially, but resistance developed. "That situation is not going to improve; if anything it will get worse."

He added that there was as yet no product providing "fully effective" control of headlice. Headlice did not pose a medical danger but people could consider them socially distressing or a stigma.