One in four smokers thinks hand-rolled tobacco poses less risk to health than manufactured cigarettes, a study says.
One in four smokers uses roll ups
The proportion of smokers who roll their own has doubled since 1990.
But a survey of 1,000 smokers by the NHS Smoking Helpline found many did not understand the risks - some research suggests roll-ups are more harmful.
It comes as a World Health Organization poll to coincide with World No Tobacco Day found more teenagers were smoking non-cigarette products than cigarettes.
A series of events will be held across the world on Wednesday to mark the day and raise awareness about this year's theme - "deadly in any form or disguise".
Public health minister Caroline Flint said: "It's so important that we de-bunk the myths associated with rolling tobacco - it's not less harmful, it's not more natural and you're just as likely to develop smoking related illnesses."
The research by the NHS helpline showed 24% of smokers use roll-ups, a rise from 11% in 1990.
Many said their motivation was because they were cheaper and made them smoke less, but experts said it was worrying how many also incorrectly cited health benefits.
Studies have found roll-ups are more likely to cause lung and oesophageal cancer.
Professor Martin Jarvis, an expert in tobacco dependence at University College London, said: "Smokers are attracted to own-rolled because they offer a cheaper nicotine fix.
"But they should not delude themselves that they are somehow more natural or less toxic."
The WHO survey of 750,000 13 to 15-year-olds across the world also suggested worrying trends.
It said that 11% of teenagers smoked tobacco products other than cigarettes, compared to 9% smoking cigarettes.
It blamed misleading marketing campaigns which left the impression non-cigarette smoking was less dangerous.
As well as roll-ups, the report said waterpipes or smokeless products such as snuff or snus were becoming popular.
Dr Yumiko Mochizuki-Kobayashi, director of the WHO tobacco free initiative, said: "Tobacco can kill in any guise and that is why all products containing tobacco need to be regulated immediately in all forms."