As far as scrubby commercial cleansers go, Bon Ami wins for non-toxic and effective. It's never bothered *my* asthma, and as long as your tub/shower isn't fiberglass or plastic, it doesn't scratch up the surface. It contains (often seashell) calcium carbonate, if that's an issue for your lungs (most folks aren't sensitive, but if you have a seafood allergy, it can be a problem.)