If your carpets are really...how shall I put this...pungent, you may need to clean two or three times. Currently with the humid weather, our house does get a bit..redolent...and I find that on clean carpets, febreze helps. A traditional remedy is to sprinkle bicarbonate of soda on the carpet, brush in with a stiff broom, leave over night and then vacuum out (originally beat out with a carpet beater). If you decide to try this, make sure that your carpet is BONE DRY and if your carpet is dark in colour, be prepared to vacuum loads to get all the bicarb up