Thousands of lives could be saved each year in the UK if all smokers switched to e-cigarettes.
Experts at University College London say electronic cigarettes could potentially lead to 54, 000 fewer deaths every year.
That directly contradicts what the World Health Organisation said just last week - when they said they release toxic vapours and should be banned indoors.
Now researchers say that's 'misleading' and 'alarmist' - and say the levels of toxins are very low.
Sheila Duffy is from the anti-smoking charity, ASH Scotland:
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