Remove everything possible from the bathroom, such as shower curtains, towel bars, clutter on the counter top and bathroom rugs. Depending on the extent of the peeling, this could be a messy job. Open windows or use fans for ventilation.
Scrape loose and peeling paint from the surface using a chisel-edged paint scraper.
Clean the walls and ceiling with mild cleanser and clean, lint-free rags or a sponge to remove hairspray, soap scum and fingerprints. The Paint Quality Institute recommends a mixture of three parts water to one part bleach to remove mildew.
Sand all painted surfaces with 120-grit sandpaper or a sanding sponge.
Prime the peeled areas with oil- or shellac-based stain-blocking primer. If the entire bathroom was peeling, prime the entire bathroom. Allow it to dry according to label directions and apply two coats of high-quality bathroom paint.
Turn on the bathroom vent fan every time you take a shower or use the bathroom. If you do not have a fan, keep the window or doors open or use a fan to direct the humid air out of a window or door.