The best thing for fleas and ticks on dogs AND cats is to add just a bit of vinegar to their drinking water. Usually 3-4 tablespoons per gallon (adjust for how much water you leave for your dog). My sister had problems with fleas from her two dogs and I kept telling her to add the vinegar. She finally did, voila! no more fleas. The vinegar is a wonderful homeopathic alternative to chemicals that do who knows what to your animal.