[Ewierl]

Regeneration ignores disease. It allows the unit to regenerate to its full normal HP total.

I don't know if this is a bug or WAD, but it produces some odd effects, where you need to put your old-age mages into combat every once in a while so they can heal up the damage lost by disease. IMO, there's an inconsistency going on if units can do something easily during combat that can never be accomplished outside of a battle!