This is taken directly from 'help magic resistance'.
Quote:
The downside to magic resistance is that it does not discriminate between helpful and harmful magic. Magic resistance may cause you to resist buff and curative magic. However, most resistance comes from equipment that has been enchanted with the enchant armor spell, which can be removed when necessary. Also, magic resistance works by absorbing magical energy and converting it into healing energy that affects the wearer. This healing effect becomes increasingly powerful as you acquire more resistance.
Unfortunately, the bold/underlined part of of this post does not seem to function at all, as i've never seen a single percent of healing from resisting -anything-.. Can this be enabled please, oh please please please? I'll love you for ever and ever.. or not, if that would convince you to enable this golden nugget of tasty awesomeness.. No, I'm not rambling! [threat] enable this feature or I'll roll another obnoxious third-person-talking, brain-cookie-eating sprite to annoy your player base! [/threat]