The Medical Association of Thailand has come out strongly against the proposal by Digital Economy and Society Minister Chaiwut Thanakamanusorn to legalise the sale of e-cigarettes.
The association sent an open letter to Prime Minister Prayut Chan-o-cha asking him to caution the minister.
The letter was signed by Amorn Leelarasamee, president of the Medical Association of Thailand, and supported by heads of other organisations, including 14 royal colleges and the National Alliance for Tobacco-Free Thailand.
In the letter, Dr Amorn said that in his proposal to the cabinet on Sept 28 Mr Chaiwut openly showed he fully supported the legalisation of the sale of e-cigarettes.
This was despite both the Commerce and Public Health ministries having no policy to allow their importation.
Dr Amorn said e-cigarettes were produced by firms in the tobacco industry to replace ordinary tobacco cigarettes.
Results from worldwide research showed e-cigarettes were clearly hazardous to health, Dr Amorn said.
In the United States, where e-cigarettes are legal, many young people who had not smoked before were found to have become addicted to vaping, because they had been fed false information, Dr Amorn said.
He said e-cigarettes, like tobacco cigarettes, contained nicotine, a narcotic substance which caused many chronic diseases that required costly treatment.
Liquid flavouring from flowers and fruits was added to the fluid used in the vaporiser to give it a sweet smell. But these substances could cause many types of cancer after being heated and inhaled, he said.
The president of the Royal College of Physicians of Thailand, AM Anutara Jittinand, said producers of e-cigarettes did not give full information about their products. They said only that e-cigarettes could help people quit smoking, but did not say how to quit vaping after becoming addicted to it.
Advertisements posted on social media by e-cigarette product producers tempted young people to try vaping, even though it is not only harmful to health but also damagig to the economy.
Countries where young people have become addicted to vaping have to allocate extra budget funding for the treatment of their illnesses, he said.
The president of the Royal College of Surgeons of Thailand, Prof Pramuk Mutirangkura, joined opposition to legalising the sale of e-cigarettes.
Responding to Mr Chaiwut's assertion that at least 67 countries had approved e-cigarettes as being less harmful than smoking tobacco, Dr Pramuk said that each of those countries had allowed the sale with conditions attached. They were not sold without restrictions, he said.
Many other countries still banned e-cigarettes because they wanted to protect the people's health, preferring the "prevention is better than cure" principle, Dr Pramuk said.