Hyperhydration

[MithrilDragon]

This is way better than my suggestion of magical violent diarrhea from over-use of potions.

But in all seriousness- Few things irritate me as much as seeing unreasonable quantities of potions/consumables being used. My feelings are that they're supposed to be used relatively infrequently with perhaps a more severe impact on combat. While this suggestion might be over-doing it, I do think that in a relatively low magic world, potions could be limited more than they currently are.

[Nihm]

Wands cannot be used as rapidly as potions.  As far as I know, you get one wand or item charge per round.  Potions can be chugged at the rate of two per round, more if hasted.
 
It forces anyone who wants to face off against the "best" (read: has more potions) fighter in pvp, or even a tournament where potions are allowed to have to scramble to get tonnes of them before they even have a chance.
 
We don't have people with plus five fullplates, swords and haste boots that make them untouchable, but do have people that have so many potions it would take a mob of people with multiple dispels to bring them down.  It's just as high a barrier when someone can drink all day and have more benefits than plus five loot gives.

[MisterPAIN]

Haste makes wand useage just as good.  More potions and consumables also makes weaker build characters win too.