The term "dog flea medicine" refers to any medication or treatment that is used specifically for dogs to prevent, treat or control infestations caused by fleas. Fleas are small parasites that feed on the blood of animals and can cause irritation, itching, and skin infections. Dog flea medicine comes in various forms such as topical solutions, collars, sprays, shampoos or tablets to help control these pesky insects from infesting your dog's fur and causing discomfort.