A new South African study suggests that smokers who try to quit by switching to electronic cigarettes, devices that deliver nicotine vapor instead of tobacco smoke, are more likely to succeed than smokers who use other nicotine replacement products. Doctors in Cape Town gave Dutch-made Twisp e-cigarettes to 349 patients. After two weeks 6 percent of the patients had stopped smoking, and the quit rate rose to nearly half (45 percent) after two months. By contrast, a 2002 study in the journalAddictionfound that the six-weekquit ratewas about 16 percent for smokers chewing nicotine gum and about 19 percent for smokers using nicotine patches. After six months, those rates fell to about 8 percent and 9 percent, respectively.