Youths are putting people at risk by posting smoke bombs through letter boxes and releasing them in the stairwells of flats.
Police and the Fire Service in Scotland are warning of the new craze.
It is understood they are using devices bought from joke shops, and from plumbers’ merchants, who market them for chimney testing.
Fire crews in Fife have recently had to deal with a number of incidents at homes and in common closes in what police described as a “glorified game of ‘chap door, run’.”
The most recent incident happened in the early hours of Wednesday on Langside Drive in Kennoway, where a smoke bomb was pushed through the letterbox of a semi-detached house, setting off the fire alarm and putting the householder in a panic.
A similar incident took place at West Leven Street, Kirkcaldy, last week.
A police spokesman said it is most likely youths activating the devices for a “laugh” with their friends.
Iain Brocklebank, from the Scottish Fire Service, said: “The use of these devices in inappropriate locations causes fear and panic to householders.
“It may also result in sufficient inhalation of smoke to cause irritation of the respiratory tract and lung damage.
“Smoke bombs produce a large amount of smoke that does not quickly disperse and improper use can be dangerous and harmful.
“Under some circumstances they can also ignite flammable materials therefore proper precautions must be taken to prevent fires involving combustible materials or in dry field conditions.”
Police are investigating the use of smoke bombs in circumstances that place people at risk.
Inspector Donald Jenks said: “Letting off smoke bombs isn’t simply a lark or a bit of fun but can put people at risk.
“In some circumstances this could be considered to be reckless conduct, damage could be caused and people injured as a result.”