A sharp rise in the number of people poisoned by swallowing e-cigarette liquids has been reported.
Experts have urged users to ensure liquids are stored safely.
Last year there were 139 calls from health professionals seeking advice on how to treat members of the public.
But there were only 29 cases in 2012, and 36 across the five years before that, figures obtained by the Guardian from the National Poisons Information Service (NPIS) show.
Over a third (36.5%) of calls involved very young children, 56% over 18s and the rest children of five and over and teenagers.
Most poisoning cases were accidental, with symptoms short-lived symptoms including vomiting, nausea, dizziness and abdominal pain.
NPIS director John Thompson told the Guardian: "E-cigarette usage has increased significantly in recent years. The liquid found in e-cigarettes can be very harmful and I would urge anyone who uses e-cigarettes to make sure that the liquids are stored safely, and in particular away from children.
“While any cases of poisoning are of concern, our previous research showed that fortunately fewer than one-in-ten of patients developed symptoms of toxicity which lasted more than four hours and only two patients had long lasting symptoms.”
E-cigarettes have been on sale in the UK since 2005, and figures from the Electronic Cigarette Industry Trade Association show that two million people currently use them.