From the outside, the hookah bar looks like a small café with dark velvet curtains hanging in tinted windows. The music of the Middle East filters faintly through the patrons' chatter as they walk in the front door.

Inside, an overwhelming smell of sweet, fruity smoke fills the dim room. Customers order snacks and cups of tea as they deliberate over their main course--flavored tobacco. The menu lists options like spiced chai, passion-fruit, and something called "Mandarin Zest."

After customers choose a flavor, the waitress brings out the hookah--a tall, statuesque pipe that draws the tobacco smoke through a bowl of water to cool it. When the charcoal bricks on top of the bowl are lit, giving off a faint smell of car exhaust, customers begin to take turns sharing puffs through a long hose attached to the middle of the pipe. First-time users often prepare to take the kind of forceful draw a smoker takes on a cigarette, but using a hookah is as effortless as breathing.

Hookah came to the United States in the 1960's with the hippie movement, but today it permeates college culture. Hookah bars usually dot the edges of college campuses and are filled with young people talking, relaxing, and laughing as they pass the pipe. Hookah use is on the rise, particularly among college women, say researchers, who fear young adults indoctrinated against the dangers of cigarettes are clueless about the negative effects of flavored tobacco.

Hookah smoke is cool, so users don't experience any of the harsh burn that comes from cigarettes. They feel their lungs fill up with something just slightly denser than the air they're used to. The flavor is so strong that it overwhelms whatever tobacco is in the bowl. It's just like inhaling a vaporous passion fruit.

According to a new study by the Center for Behavioral and Preventative Medicine at The Miriam Hospital, in Providence, R.I., 23 percent of female students try hookah during their first year of college. And of the 483 females interviewed for the study, 140--29 percent--had already experimented with hookah before arriving on campus.

"This rate is generally consistent with other recent studies, which show that hookah use among American adolescents and college students is not uncommon," said study author Robyn Fielder. "Comparing our results to earlier studies suggests that prevalence may be increasing."

Fielder, while concerned about the public health risks posed by frequent hookah use, believes that much of the impetus behind the activity is youthful experimentation. Trying tobacco is just a way of developing an identity--part of being a college student.

"We found that 45 percent of the women who tried hookah reported using hookah during only 1 month out of the 12 month follow-up period," Fielder said. "Thus, many women simply tried hookah once or twice, but did not become regular users. They decided notto continue use of tobacco in this form. So, this is actually good news."

While the novelty may be attractive, an additional draw for students could be the social aspect. Hookah pipes are usually shared between small groups.

"It's a little thing to do between talking, makes it a little more comfortable when you're with new people," said Rachel Jardini, a rising senior at Temple University, in Philadelphia, Pa. Jardini tried hookah for the first time during her first year of college. "That's what was cool about that hookah circle on campus. It was a collection of strangers, freshmen, who just gathered and had an excuse to keep sitting next to each other."

Although researchers fear hookah use could act as a gateway to marijuana use, current studies don't offer enough data to draw any definite conclusions, Fielder said.

Health experts are more concerned that many students who try hookah believe that it is no different, and probably healthier than, smoking a cigarette. But a hookah pipe actually gives off about 100 to 200 times as much smoke as a cigarette, according to the Centers for Disease Control.

"I had no idea," said Taylor Flynn, a senior at Boston College in Massachusetts. "I'm usually down to roll, but I don't know if I want to put my lungs through that. I probably won't be doing that again."

Jardini knew about the health effects, but they didn't worry her.

"It's just one of those dumb things young people do even though they know they shouldn't... funny how I can be aware of that and still live like that," she said. "If I were really gonna put my health first, though, I'd quit caffeine and red meat too."