Someone earlier was having trouble with ticks on their dog and said nothing worked. I've been using Seresto tick/flea collars for two years on three inside/outside dogs and they have been completely free. Collars are expensive, about $50, but easily last 8 months. DO NOT buy any on Ebay thinking you are getting a deal for $26....they are totally fakes. One dog likes to run the woods and I've found several ticks on her that were dead. Another is highly allergic to sprays but tolerates Seresto very well.