Environmental flea control is an essential part of keeping your pets free from unwelcome parasites. Defest 3 Months is the product of choice when fleas have already established themselves in your home. Apply to all rooms to which pets have had access. Combine treatment with regular vacuuming & wash all pet bedding. Due to the nature of the flea lif-cycle, once fleas have become established, it may take several weeks to completely eradicate them. Read the label carefully before using.