From the muscled tough guy with the cigarette tucked in his T-shirt sleeve to the sultry heroine lighting up during a crisis, movies popularized the habit until the 1980s when smoking in films declined. But research in the journal Tobacco Control shows smoking in films is becoming popular again.

"Regardless of the reasons, the use of tobacco in films is increasing and is reinforcing misleading images that present smoking as a widespread and socially desirable activity," researchers Stanton Glantz and Theresa Stockwell said in the study.

"These portrayals may encourage teenagers - the major movie audience - to smoke. It also appears that the problem is getting worse."

Glantz, of the University of California, and Stockwell, who works for the Central Coast Tobacco Free Regional Project in the same state, analyzed 35 major films for each year between 1991 and 1996.

They found that 4 percent of the running time for each film contained reference to tobacco smoking and that up to 80 percent of the male leads and 27 percent of the female leads smoked.

"In an era in which the tobacco industry is finding traditional advertising media increasingly restricted, the appearance of tobacco use in motion pictures is an important mechanism to promote and reinforce tobacco use," they added.

Glantz and Stockwell suggested that strong anti-smoking advertising should be run before films that include smoking to neutralize the pro-tobacco influence in the film.

They also urged producers to require everyone connected with the making of a film to certify that they are not receiving payments or gifts for the use of tobacco in the film.