I have someone asking me whether or not it is safe, but I have never used it. If anyone has used it before, I would be most obliged if you would let me know how it worked for you and if it is safe so I can pass the info on.
I dont know if this helps... Got this link for you: http://www.bio.miami.edu/hare/buttbath.html
Says: "Purchase a container of Baby Cornstarch Powder (DO NOT use Baby Powder or any sort of powder that contains talc, as talc is a respiratory irritant and may even be carcinogenic!) from the grocery store baby section. You can use either unscented or scented cornstarch powder. DO NOT use commercial flea powders or other pesticides on your bunny. Use only baby-safe cornstarch powder for best, safest results."