Revolution for cats is a monthly topical treatment that protects against six major parasites: fleas, heartworms, ear mites, roundworms, hookworms, and (in the Plus version) ticks. It’s applied to the skin between the shoulder blades once a month, and each dose provides 30 days of protection.
There are two versions available: the original Revolution, which contains selamectin alone, and Revolution Plus, which adds a second active ingredient called sarolaner to expand coverage to ticks and tapeworms. Here’s what each version treats and how well it works.
Flea Treatment and Prevention
Both versions of Revolution kill adult fleas. In controlled lab studies, over 98% of fleas were killed within 36 hours of application. The product also prevents new flea infestations for the full month between doses by killing fleas before they can lay eggs, which helps break the flea life cycle in your home over time.
Revolution Plus goes a step further: because it kills the fleas that carry tapeworm larvae, it also prevents tapeworm infections that cats pick up by grooming and swallowing infected fleas.
Heartworm Prevention
Heartworm disease is caused by a parasitic worm transmitted through mosquito bites. While it’s more commonly discussed in dogs, it can be fatal in cats, and there is no approved treatment for heartworm infection in cats once it develops. That makes monthly prevention critical.
Revolution works by eliminating the immature heartworm larvae in the tissue before they can mature into adults. Studies at Louisiana State University found that selamectin is 100% effective at preventing heartworm development when given within 30 days of exposure to infected mosquitoes. That efficacy held whether cats received a single dose or three consecutive monthly doses.
Ear Mites
Ear mites are tiny parasites that live in the ear canal and cause intense itching, dark waxy discharge, and head shaking. They’re extremely common in kittens and cats that have contact with other animals. Revolution treats and controls ear mite infestations without the need to put drops directly in the ear. The medication is applied to the skin on the back of the neck and reaches the ear canal through the bloodstream and skin oils.
Roundworms and Hookworms
Revolution treats two common intestinal parasites. Roundworms are the most frequently seen intestinal worm in cats, particularly kittens, and can cause a pot-bellied appearance, vomiting, diarrhea, and poor growth. Hookworms attach to the intestinal lining and feed on blood, which can lead to anemia and weight loss.
Both versions of Revolution treat and control these infections with each monthly dose. This is especially useful for outdoor cats or cats in multi-pet households where reinfection risk is higher.
Tick Protection (Revolution Plus Only)
The original Revolution does not cover ticks. Revolution Plus adds sarolaner, which treats and controls infestations from four tick species: the lone star tick, the Gulf Coast tick, the American dog tick, and the black-legged tick (the species most associated with Lyme disease). Each dose provides one month of tick protection.
If your cat spends any time outdoors or lives in an area where ticks are common, the Plus version offers meaningfully broader protection.
Age and Weight Requirements
Revolution Plus is approved for cats and kittens 8 weeks of age and older that weigh at least 2.8 pounds. The original Revolution has a similar profile. Your vet will select the correct tube size based on your cat’s body weight, and it’s important to use the feline version rather than a canine formulation, as the dosing differs.
Possible Side Effects
Most cats tolerate Revolution well. Temporary hair loss at the application site is the most commonly reported issue. Some cats may experience mild digestive upset or brief lethargy after application.
Revolution Plus contains sarolaner, which belongs to a drug class called isoxazolines. The FDA has noted that isoxazoline products have been associated with neurologic reactions in some dogs and cats, including muscle tremors, loss of coordination, and seizures. These events are uncommon, and most animals never experience them, but they can occur even in animals with no prior seizure history. If your cat has a known neurologic condition, this is worth discussing with your vet before starting the product.
What Revolution Does Not Treat
Revolution does not treat tapeworms directly (though the Plus version prevents them by killing flea vectors). It also does not treat whipworms, liver flukes, or other intestinal parasites beyond roundworms and hookworms. If your cat has a confirmed tapeworm infection, a separate deworming medication is needed. The original Revolution also provides no tick coverage, so cats at risk for tick-borne diseases need either the Plus formulation or an additional tick preventive.