Gutkha, which is imported from South Asia, is a mixture of betel-nut and chewing tobacco. It is addictive and is apparently being targeted at youngsters.
A new sweetened form of the product - known as Gutkha - has just found its way into shops in the UK, and health professionals are worried about the possible links to cancer.
About 3,000 people in Britain are diagnosed with oral cancer each year, of whom half will die.
Gutkha, which is imported from South Asia, is a mixture of betel-nut and chewing tobacco. It is addictive and is apparently being targeted at youngsters.
In India, where chewing tobacco is an integral part of the culture and Gutkha has been around for some time, mouth cancer is one of the most common forms of the disease.
Shailesh Modha, from Birmingham, has the disease submucal fibrosis - a pre-cancerous condition causing pain and a tightening of the mouth. It has been caught early and his prospects are good, but it was probably caused by his tobacco chewing habit, picked up five years ago.
He said: "I was very shocked - I didn't think it would be that serious. Something that was a social thing to do, I didn't think it would have such consequences."
Professor Newell Johnson, an expert in oral cancer, said: "We know that this condition, oral submucal fibrosis, has the highest rate of transferring to malignancy of any of the so-called pre-malignant lesions in the mouth. It's a very serious condition."
In Birmingham trading standards officers are issuing cautions and spelling out the law to shop owners who sell the tobacco to those aged under 16.
Ajmal Masroor, a local community worker, has called for people to be made aware of the potential dangers.
"We have to educate people so they can make an informed choice rather than do something because it is habitual," he said.