Antibiotic may turn stool red- prob for my CD's?

DS has been prescribed a cephalexin antibiotic for an ear infection.  The pharmacy technician and the drug information sheet both warn me that the medicine may give him reddish stools.  Anyone have any experience with this?  I don't want to permanently stain my CD's red.  I currently use prefolds and some BG 4.0's.  Would I be best to use a package of disposables until he's done with the antibiotic?