I don't believe Advantage Multi is considered a tick preventer. It is a worm preventer. In particular, it is commonly used to prevent heartworm, but also works on hookworms, roundworms and whipworms...as well as fleas.I'm officially less than thrilled with the Bayer Advantage Multi. I applied it about four or five days before heading to my in-laws' place in New Jersey over Thanksgiving. With very limited exposure to cover, my dog's head got covered with deer ticks. At no point did my dog get wet for 48 hours before or after application or even since application. My dog has to go to the vet first thing in the morning as it appears he has tick bite paralysis due to all the LIVE ticks we pulled off of him. So, if the Bayer Advantage Multi doesn't repel ticks and obviously doesn't kill them, exactly what is the point? Given that I live in a high heart worm infection area, it makes me nervous about relying on it for heart worms.