Fleas are stubborn parasites, mainly because they reproduce at such a prolific rate. Follow these guidelines, though, and you'll be on your way to a flea free home.
 

• Treat every cat and dog in the house
  It doesn't matter which product or combination of products you use, or whether you can actually see fleas on all your pets, ALWAYS treat every cat and dog in the house.
  
• Persevere
  In most cases, flea infestations should clear within a few days. However, flea eggs laid around your home can survive in the carpet for up to 9 months. During this time, they can hatch and jump back aboard the pet whatever treatment you use. This doesn’t mean that the product you are using isn’t working. Just that the existing infestation is clearing.
  
• If you treat the pets correctly, you needn't spray the house
  That's right. It's because all fleas will jump on your cat or dog as part of their life cycle. So if you have treated the cat or dog, they'll die out when they come into contact with the animal. This process won't be hastened by treating the carpets.
  
• To hasten flea removal from the home
  You can hasten removal of fleas by raising the temperature and humidity in the house to encourage fleas to hatch faster, whereupon they'll leap onto the pet, be exposed to the insecticide, and die out.