Mimi - when you apply the Frontline it is very important that it be applied directly to skin or it will not work. Frontline must be absorbed by the skin so it can be "wicked" across the body. If you simply apply it on top of the fur it will not work. It is not unusual for there to be a "gease spot" where it was applied but it should disappear within 24 hours. Make sure you part the fur and apply the entire amount in the tube. Do not bathe your pet 24 hours before you apply it or 24 hours after applying it or it will not be effective.

Hope this helps.