E cigarettes contain lots of nicotine. Sometimes, perhaps rarely, a cat might get hold of an e-cigarette or refill. It might break open. The cat might ingest some of nicotine and become poisoned by it. I think, to be honest, that most cases of e-cigarette poisoning of pets concerns dogs who more likely to bite on crunch open e-cigarettes and their refills. But nonetheless, cat owners should be aware of this potential danger. Veterinarians have flagged up the potential danger to pet owners. Click on the link above to read a brief summary of a report by the Veterinary Poisons Information Service in the UK.