In a double-blind randomised trial, 40 cigarette smokers used either nicotine-containing or placebo smoke-free cigarettes during 24 h abstinence from smoking. Subjects in the nicotine group experienced smaller increases in irritability and difficulty concentrating and fewer urges to smoke than those who received placebo. Nicotine smoke-free cigarettes were rated as more satisfying, more helpful and more effective in relieving craving than placebo. After 24 h use nicotine smoke-free cigarettes provided average blood nicotine levels of 6.3 ng/ml, i.e., 29.2% of smoking levels. The most frequent side effects were irritation of the throat and coughing. Overall, side effects were rated as not serious. Although the smoke-free cigarette in its present form is not very efficient in delivering nicotine, it was effective in alleviating initial tobacco withdrawal. It is possible that by providing both nicotine and "behavioural" replacement it may be particularly useful in the first stages of stopping smoking. The product is worth further investigation.