Virbac Effipro Spot On Flea & Tick Treatment for dogs is an effective treatment and prevention of fleas and ticks on dogs. It is based on a new formula containing Fipronil, an insecticide and acaricide belonging to the phenylpyrazole family.It gets to work killing pests straight away, and will usually clear fleas within a day, and persistent ticks within 48 hours. Fipronil is a strong agent that provides fast action that lasts for up to 2 weeks. A one month interval is recommended between applications.Dosages: Small dogs: 1 pipette of 0.67 ml per dog weighing over 2 kg and up to 10 kg bodyweight Medium dogs: 1 pipette of 1.34 ml per dog weighing over 10 kg and up to 20 kg bodyweight Large Dogs: 1 pipette of 2.68 ml per dog weighing over 20 kg and up to 40 kg bodyweight (For dogs over 60 kg use two pipettes of 2.68 ml.)WARNINGS Do not use on sick or recovering pets Do not use on rabbits, it could be fatal Do not use if your pet is allergic to any of the ingredients Do not get in eyes Do not allow the pet, or other pets to lick the treated area Keep treated pets separated from children until the application is dry