Advocate treats, protects against and prevents the major parasites of your pet, inside and out. Treat- Eliminate existing parasite infections. Protect - Continuous coverage, as one application lasts all month. Prevent - New infections cannot establish. Advocate is the most convenient way to protect your pet as it is the only spot-on product to control fleas, heartworm and gastrointestinal worms in dogs. That means no more nasty tablets for your dog.