Advantage Dog with imidacloprid as active ingredient works preventively and curatively against fleas and biting lice. The product stops fleas biting in 3 to 5 minutes and kills adult fleas within the hour, before they can lay eggs. The fleas present on your dog are all killed within 24 to 48 hours of administration. In addition, Advantage Dog prevents re-infestation. Advantage Dog can also be used to treat biting lice in dogs. A single treatment with Advantage Dog protects your dog against fleas for 4 weeks. Advantage Dog can also be used as part of a strategy to treat flea allergy/dermatitis.