Laura McKirdy, a vet at Dalston-based Paragon Veterinary Group in Carlisle had to put down a dog which had chewed on its owner's cigarette device.
She said the dog she put down - which was a cross breed - showed signs of the effects of a nicotine overdose.
It had poor co-ordination and was sensitive to light, sound and touch.
She warned owners to treat their e-cigarettes in the same way as they would medicines and keep them out of reach of dogs or anything else that might accidentally eat them.
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