My sweet cat Licorice, an indoor cat, somehow got fleas. I didn’t have a lot of money, so decided to “cheap out” and get the Hartz Flea drops at Canadian Tire.. 3 for $8.. wow, I thought, in comparison to $20 for the Advantage or Revolution, this is a good deal. BOY was I wrong! My poor baby developed a horrible reaction/allergy to this product and got several large oozing sores all over his neck and head. I happened to be away and my poor Mom had to take him to the vet, after extensive treatment, and ointment my cat did combat the issue. I would NEVER use this product again and would urge any pet lovers to boycott all HARTZ product. This company clearly do not love our pets.