One of our customers has had first hand experience of this recently. One cigarette butt can contain enough nicotine to poison a dog. Especially puppies and smaller breeds. What can happen Nicotine Poisoning Effects on Dogs: Signs, Concerns & Treatment (Vet Answer) Hepper Pet Resources General poisons Dog health The Kennel Club Frontiers Dog and cat exposures to drugs of abuse identified by the California animal health and food safety laboratory system 20132023