Spray to back, sides, stomach, legs, shoulders, and neck. For head and eye area, spray on a gloved hand and rub gently into pet's hair, do not get product in pet's eyes or mouth.
All existing fleas will die within 24 hours. The time to completely remove the infestation will very depending on the extent of the flea infestation. If fleas are also in your dog's environment, then new fleas that hop on will take up to 24 hours to die.