[Britster]

I think most say 24-48hrs. Frontline states:

FRONTLINE Brand Products remain effective for 30 days, even if a pet swims or is bathed. After application, keep the dog or cat from getting wet until the application area appears dry, usually 24 hours. If a FRONTLINE Brand Product is to be applied after a bath, make sure the pet is completely dry before application.

I also HATE the greasyness that it gets on Jackson's hair! Ugh. I put Frontline on him last night but luckily, it's pretty dried up this AM. I had one tube of Frontline left so wanted to get use out of it... hopefully it works for us, as usually in summer Frontline doesn't work as well, so we've gotta use K9 Advantix (which he'll be going on next month).