A study found that chemicals in the devices can impair the processes that allow the body to repair itself.
The findings may explain why some users can develop persistent painful mouth sores and ulcers. E-cigarettes are widely promoted as a safer replacement for tobacco.
But toxicology experts in the US say they can lead to a range of health issues. A study by the University of Rochester in New York, published in the journal Scientific Reports, exposed damaged lung tissue to e-cig vapours in the laboratory.
They found the nicotine and flavour chemicals prevented certain cells getting enough energy to heal a wound properly. Study leader Dr Irfan Rahman said: ‘While it is perceived that they may be less harmful than conventional smoking, our data shows e-cigarettes can lead to other health issues apart from lung damage.’
Public Health England said that despite the results, e-cigs remain much less harmful than smoking tobacco.