Health

Your overall health can be assessed by taking into account your current hit
points as well as realizing wheather you are diseased or not.  All living
objects, monsters and players alike, have a certain level of healthiness.
This can be determined by looking at the living being.  It is the last line
of its' description, before its' inventory listing.  The more hit points the
monster or player has, the healthier it is, naturally.  
Only players can contract diseases.  Diseases are curable by clerics.