GPs in a city say they are seeing an increase in teenagers with health problems linked to shisha pipe smoking.
Leicester's Primary Care Trust said it had been surprised by the numbers visiting doctors with symptoms.
Qasim Chowdary, a PCT smoking cessation adviser, said the increase in pipe use, which involves burning fruit flavoured tobacco, was among 15 to 24-year-olds.
He said research challenged the "misconception" that shisha smoking was not as harmful as smoking cigarettes.
He said shisha pipe smoking was now incredibly popular among youngsters of all cultures and ethnicity whereas the practice had been non-existent among the age group a few years ago.
Shisha is an Egyptian word for water pipe or, hookah. Fruit flavoured tobacco is burnt on top of lit charcoal and the smoke is then sucked through the pipe.
Mr Chowdary said: "There is a massive misconception that shisha smoking isn't as harmful as cigarette smoking. In fact research by the World Health Organization has shown an average pipe smoking session of around an hour is equivalent to smoking up to 200 cigarettes."
The health risks are similar to cigarette smoking, including respiratory and heart disease.
The smoke contains carbon monoxide and pipe smoking can also transmit infections and viruses such as oral herpes and tuberculosis.
Govind Mandora, Leicester City Council's health and safety team manager, said: "There are now a dozen shisha cafes in Leicester. Four years ago there was just one. It's increasing in popularity across the country."
Majlis Shisha Cafe is located on the roof of a furniture showroom close to the city centre.
It moved to the roof of the original premises following the smoking ban in in 2007.
To comply with the smoking regulations a vast wooden canopy covers the top of the roof but there is a 1.5m gap to the surrounding wall.
There are a large number of patio heaters to keep customers warm as they sit on the soft sofas smoking the pipes and chatting.
It is so popular that on a Saturday night there can be a 30 minute wait to get in.
The owner, Zubair Contractor, is aware of the health concerns but believes there has not been enough research into the harmful effects.
He said: "There's no alcohol, just soft drinks and snacks. People come to chat and have a smoke. I have a friend who smokes three times a day and he is showing no health symptoms.
"We also use natural charcoal, not swift lights with chemicals."
Even on a weekday in the early evening there is a bustling atmosphere.
Layla Ibrahim is a 23-year-old student originally from Somalia.
She settled in Leicester several years ago and visits the café once a week with her friends.
"We are aware that's it not good for you but we forget when we're having a good time chatting and having a smoke," she said.
"Shisha is now very much part of the UK culture. The health risks depend on the quality of the tobacco and the way it is mixed with fruit or herbs. Not all of it is really harmful.
"I'm not going to stop coming, I enjoy it. If there's more fruit and less tobacco it's less harmful"
Leicester City Council is working with other agencies to ensure all shisha cafes comply with smoke free regulations and smoking is not taking place within enclosed premises.
Already a number of shisha cafes have been prosecuted for flouting the law and more are being taken to court.
Mr Mandora says the council is receiving weekly enquiries about how to open up a shisha cafe.
He is also receiving enquiries from local authorities across the country, who are dealing with the burgeoning shisha café culture.
"Councils from Manchester to Tower Hamlets in London, Bristol, Bradford, Coventry, Swansea and Birmingham have all been in touch," he said.
"We don't want it to become acceptable like cigarette smoking."