The problem with diatomaceous earth would be particle residue in the bun’s fur. The bun would ingest some, and it would also inhale some of it. Even if DE is non-toxic, it can do mechanical harm to the lungs. Prolonged exposure to DE has been linked to silicosis of the lungs in humans. Bunny lungs are tiny and delicate.

You can use DE away from the rabbit go get rid of fleas in the environment, but it must be very carefully vacuumed away before the bun is let back into the area. DE is a natural product, and I applaud you for wanting to use natural products instead of chemicals – but natural doesn’t necessarily equal harmless.

I’d choose Revolution or Advantage for use on the bun. Advantage is OTC.

And now for a warning we always issue when skin parasites are mentioned: Do not use any compound containing fipronil on a rabbit. Fipronil is sold under a whole host of brand names, for example Frontline. Fipronil is deadly toxic to rabbits.

Its the aromatic oil in cedar that is the problem with using cedar shavings etc for rabbit. So I would say wondercide would have same risk. The oil can cause eye and respiratory irritation, but it also can elevate certain liver enzymes.

If you haven’t found any fleas on Cake, I’d do a topical flea product like Bam suggests. It will act as a preventative, where as DE wont.