A woman exhales the flavored vapor from a disposable e-cigarette.Photo: Li Hao/GT

What's the easiest way to break a bad habit? Replace it with a new one. Smokers who have struggled to stub out their craving for nicotine are turning to e-cigarettes in droves. With their familiar shape and flavored vapor, these trendy gadgets help satisfy habitual tactile, visual and olfactory cues. Smokers can watch the vapor slowly escaping from their mouths, creating an intoxicating swirl even as they experience the ecstatic lightheadedness in a new way.

"Unlike with traditional cigarettes, consumers can choose from various flavors of e-cigs, such as strawberry, apple, blueberry and so on, to reduce their addiction to the taste of tobacco," said Fanny Fang, an online vendor who has sold the devices for four years. "It does work for many smokers. However, the most crucial factor in quitting is the determination to quit."

For smoking cessation, Fang recommends e-cigarettes that use refillable cartridges of liquid smoke that dispense varying amounts of nicotine - 12, 6 and zero milligrams - which can help smokers gradually reduce their dependence on the drug.

Jonathan Brown used to be a self-described "tobacco junkie" who needed 15 to 20 cigarettes per day for the pleasure of "oral fixation and tangibility of breathing out some kind of smoke." Rather than choosing to chew nicotine gums or wear nicotine patches, he decided that using e-cigarettes was the most efficient way to manage the symptoms of withdrawal.

"The e-cigs allowed me to continue my habit of blowing out smoke from my mouth with much less nicotine content," he said. "I sort of liken it to drug addicts coming off heroin with methadone. It wasn't too much of a change."

Brown, 32, received an e-cigarette kit from his friend as a birthday gift. "I'd say it took about four months of smoking the e-cig before I was free of everything," he said. "It's a nice bit of security if I find myself in a moment of weakness. It's still better than going back to real cigarettes and having to climb the smoking cessation mountain all over again."

He cannot claim to have fully quit smoking real cigarettes, because he picks up those old friends occasionally for a puff. "That's why it's better to never start than to quit," Brown advised.

This accounts for the controversy around disposable e-cigarettes. Though they are all nicotine-free, they look like toys, Fang says. In fact, some ads on taobao.com suggest that they can be given as presents to kids. "The chemicals, which include glycerine and artificial spices, will definitely harm children's health," said Fang. "Also, developing this habit might result in them becoming actual smokers."

Cheng Meng is an example of someone who started out with nicotine-free e-cigarettes and ended up smoking Marlboros. "My boyfriend gave me [an e-cigarette] when he came back from a business trip. I loved the feeling of holding it between my index and middle finger, and deeply inhaling the sweet smoke," she said. Cheng bought more e-cigarettes for herself from taobao.com. Then one day, when she saw a couple of her female colleagues smoking outside her office, she joined in - and started down the road of tobacco addiction. "I know I should have stopped myself in the very beginning," said the 31-year-old. "But smoking is not only a form of refreshment - it also allows me to blend in better at my workplace."

In her opinion, people should only give e-cigarettes to people who are already smokers. "Otherwise, some tend to indulge themselves in sensory pleasures might develop a smoking habit, just like me," Cheng said.