You want to quit smoking? Naturally.

A herbal remedy for depression might also help smokers kick the habit if research underway at the School of Pharmacy at the University of London proves positive.

The research headed by Elizabeth Williamson is looking into the effects of St. John's Wort (Hypericum perforatum) on 200 smokers. The herbal medicine is commonly used in Europe for treating certain kinds of mild to moderate depression. Advocates of St. John's Wort claim it to be non-addictive and free from the usual side-effects of conventional antidepressants. Indeed, many general practitioners in Germany prescribe it in preference to those drugs.

Williamson suspects that St. John's Wort might help redress the balance of the neurotransmitter serotonin and dopamine during the time when smokers have their first craving of the day. This would help them replace the morning coffee and cigarette with a hearty breakfast and so ensure sufficiently high blood sugar levels to avoid mood swings later in the day. Women, in particular cite mood swings as one of the major reasons for not giving up.

"Recruitment into the trial will close at the end of March 2001," says Jo Barnes, the pharmacist running the study. Preliminary results will be presented at the 6th ESCOP symposium in Bonn (May 10-11).