Fleas! (x-posted in Nat.Home and body care)

Use baking soda! Baking soda and/or vinegar solves pretty much anything.

Here are the instructions for eradicating fleas from Frugal Living (http://frugalliving.about.com/cs/tip...gsoda1_2.htm):

Mix equal parts of table salt and baking soda together and sprinkle over the carpets. Instruct several children (or volunteers) to run all around on the carpets until the soda and salt is no longer visable.

Let set overnight. Vacuum carpets carefully, going over it more than once. All adult fleas should be dead or too thirsty to breed. Fleas go through at least one life cycle in which they are impervious to nuclear devices, so you will need to salt and soda your carpets two more times to kill all the fleas and potential fleas. Dusting your dog with baking soda several hours before a bath will kill a lot of fleas and a lot of odor. But be sure to wash or rinse the baking soda off the dog or the dog could be at some risk of skin trouble.

Caution! Do not try this on a rainy day! You will wake up to wet carpets as the salt pulls the moisture out of the air. If you live in a damp climate, sprinkle soda and salt in the morning. Vacuum 3 - 5 hours later.

I know you x-posted to natural home and body care, so you may not like this answer, but the consensus here is that the natural remedies don't really work, or don't work consistently. Fleas were here long before we were, and they're incredibly resistant to environmental changes, including things like dessication (borax and salt are dessicants, which is why they do work on some insects). And fleas are not just nuisances--they're health hazards. Fleas give animals (and, rarely, people) tapeworm infestations, and they cause infected bites, hot spots, and other nasty things. I haven't owned a can of OFF in years, but I will and DO use Frontline and Advantage for fleas.

What meds are the animals getting? That will stop a lot of the cycle right there if they're getting good stuff. For the carpets, I think that the "bombs" are pretty bad and I know they trigger my sensitivities like crazy. What worked for us the one time it got bad (new house; I think that fleas take advantage of changes, like construction or new moves) was Frontline (that particular brand name, not anything else) spray along all of the edges of the room, under couches and beds, and vigorous, multiple-times-a-day vacuuming with a very good vacuum. Since my kids don't generally play at the edges of a room or under the couches, I felt that their exposure was minimal, and when it was paired with Frontline on the dogs and cats our problem was over in a week or two.