It's completely natural and safe, even to ingest, to us and animals. It's mechanical not chemical. Here's a link that explains it very well.http://www.shadowridgedonkeys.com/perma_guard_what.htmhttp://www.dirtworks.net/Diatomaceous-Earth.html
(they are very expensive though)
You can also buy direct from Perma-Guard.
Just make certain you get the Fossil Shell Grade
which is safe for us and animals to eat. You *can* use the D-20 Pet & Animal one which is still safe to rub in their coats, but it is not meant for ingestion. This one is a lot more expensive, but also recommended only if you have a major infestation.
And even if you do have a major infestation, you can still use the Fossil Shell, it *will* work, but it will take a little bit longer.
If you get some, you will need a container to store it in and you can buy one at Wal-Mart.
The DE looks likes a powder, almost like flour so yes it can be messy, but it is well worth it. It's also important to wear a mask and goggles when treating your house and to keep the pets away until it has settled. It's just that it's not recommended to breathe it in, just like you wouldn't want to breathe in baby powder etc.
Also keep in mind that it's almost impossible to get rid of fleas 100%. There are always going to be some that get inside the house just by us going in and out. They can jump on your socks. They live outside in the earth, and gardens, and grass. Here's a link on fleas, their life cycle, etc.
But with the DE you can treat your house more than once safely, and you can lightly rub some in your pets coats.
If you have a very bad infestation now and don't want to wait the 7 - 10 days it will take to receive it, I would go to my vet and ask for a prescription to get some advantage. You can get a pkg with 4 doses for $50 until the earth comes in and that will start to kill the fleas etc. within 10 mins.
Vacuuming is good! Depending on how good your vacuum is, it can help to suck up the cocoons in the carpet. But you need to empty the bag or container outside right after.