A. Myna, I sympathize with you. Every year I talk with many clients who have had to spend considerable sums to rid their houses of fleas. Luckily we have some very good prescription medications which when started early in the spring will make sure your pet doesn't become infested with fleas and will prevent your house from becoming overrun with these pesky little critters. For so many years we depended on marginally effective collars, messy sprays and smelly dips. When the female flea feeds on your pet's blood the chemical in Program enters her eggs and causes a change in the egg that prevents them from hatching.
Programs has some drawbacks, though.
Since it doesn't kill adult fleas you may still see some biting your pet. If your pet is allergic to fleas he will still get the allergy because the flea has to bite him to become sterile. Finally, all the pets in the house whether they go outside or not will need to be taking program. Fleas that feed on pets not taking program will be able to lay eggs to infest your house. On the other hand, Program works well, is given as a monthly pill to dogs and as a shot that lasts 6 months in cats.