Advantus is an oral flea treatment for dogs formulated as a flavored soft chew that can be fed by hand or offered as a treat. The active ingredient, imidacloprid, is absorbed and works to paralyze and kill adult fleas when they bite the treated dog, with activity beginning within about an hour of dosing. It is intended for use once fleas are already present, since it does not prevent future infestations or affect flea eggs or larvae in the environment. Dosing is based on the dog's weight, with one chew strength formulated for smaller dogs and a separate, higher strength for larger dogs. Chews are packaged in a bottle and can be repeated once daily if a dog becomes reinfested with fleas. The product is intended only for dogs and puppies at least 10 weeks old and weighing 4 pounds or more, and should be stored at room temperature out of reach of children and pets.