To keep fleas off your carpet you should vacuum regularly.  If, however, you already have fleas on your carpet then vacuuming alone will not work because, although it may get the fleas themselves it will still leave eggs and larvae.  Therefore, you will need more targeted carpet flea treatment. 

The two options towards carpet flea treatment are chemical and natural.  The advantage of the chemical route is that it is a faster and more effective method of removing the fleas.  However, the chemicals can be of danger to your pets, children and adults therefore the environment must be carefully controlled when the carpet is being treated.  The reverse is true for natural alternatives; they will not be harmful to anything but the fleas, however there is a risk that they will not work as well and they will not be as quick.

Which is the best carpet flea treatment for your situation would best be discussed with your vet.  However, in general terms, the more fleas you have on your carpet the more in need it is of the chemical carpet flea treatment option.  However, this should probably be avoided if you are using it in an area in which you cannot keep children or pets out of as it could prove dangerous.  On the other hand, if the infestation is not too serious or you cannot guarantee that children or pets will not enter the room that is being treated, then a natural option is probably the best choice.

In fact, it is best to use a natural option if it is at all feasible.  For one thing, it is the cheaper carpet flea treatment, so will benefit you.  The other reason requires a slightly wider, more long term view, which is that fleas are becoming immune to chemical treatments.  This is because certain fleas will naturally not be affected by the chemicals, and they will breed, producing a higher number of fleas which are not affected by the chemicals.  In this way, eventually, fleas will become immune to all chemicals and new ones will constantly need to be invented.  Therefore, the more sparingly chemical solutions are used the better.  Natural solutions do not suffer from this same problem.