Wish

The wish spell is a more potent version of a limited wish (q.v.). 

If it is used to alter reality with respect to hit points sustained by a party, to bring a dead character to life, or to escape from a difficult situation by lifting the spell caster (and his or her party) from one place to another, it will not cause the magic-user any disability. 

Other forms of wishes, however, will cause the spell caster to be weak (-3 on Strength) and require 2 to 8 days of bed rest due to the stresses the wish places upon time, space, and his or her body. Regardless of what is wished for, the exact terminology of the wish spell is likely to be carried through.

(This discretionary power of the referee is necessary in order to maintain game balance. As wishing another character dead would be grossly unfair, for example, your DM might well advance the spell caster to a future period where the object is no longer alive, ie. putting the wishing character out of the campaign.)

THE EFFECT OF WISHES ON CHARACTER ABILITY SCORES

It is quite usual for players to use wishes (or alter reality spells found on scrolls) to increase their ability scores in desired areas, whatever the areas might be. It is strongly suggested that you place no restrictions upon such use of wishes. 

However, at some point it must be made more difficult to go up in ability, or else many characters will eventually be running around with several 18s (or even higher!). Therefore, when any ability score reaches 16, then it should be ruled a wish will have the effect of increasing the ability by only 1/10th of a point. Thus, by means of wishes (or wishes and/or alter reality spells) a Charisma score of 16 can only be raised to 17 by use of 10 such wishes, the score going from 16 to 16.1 with the first wish, 16.2 with the second, and so on. 

This is not to say that magical books or devices can not raise scores of 16 or better a full point. The prohibition is only on wishes.