This product is fantastic. I am an avid hiker and spend nearly every day in the woods for at least a couple hours. I am not sure how this works for fleas, but it works great to help keep ticks off the dogs. I have used just geranium oil in the past and know it works awesome for ticks. Also, may of the flea/tick products my dog can't stand the smell and will instantly try to rub it off. This product doesn't seem to bother him and he smells great! I highly recommend you try it and I do reapply it every time I go out.