The reason why a dog foams at the mouth may be because it accidentally licks pungent food such as chili pepper, mustard or bitter medicine, causing it to continuously flap its salivary glands and secrete saliva continuously.

It may also be due to the symptoms of vomiting due to parasite infection in the dog's body. Normally, the dog can be given antiemetic medicine and anti-inflammatory drugs. After taking it for about five to seven days, the dog will recover normally.