What happens when dogs eat cigarettes?

The nicotine in cigarettes is toxic to dogs and can be lethal, depending on the dosage, so cigarettes should be kept out of reach for dogs at all times. The exact dosage of nicotine that can cause harm to a dog depends on the dog's size with the approximate toxic dosage being 1/2 to 1 milligram per pound of the dog's body weight, reports the Mar Vista Veterinary Clinic.

Nicotine can cause symptoms in dogs in as little as one hour that include collapse, tremors, abnormal heart rate, weakness, vomiting and incoordination. Electronic cigarettes, nicotine gum and nicotine lozenges are also toxic and can have the same negative effects.