Of Potions

1. Potion Toxicity

Medication has a window on how frequently it should be taken, energy drinks say to limit how many you should consume a day, and there are plenty of articles about how much or how little caffeine we should consume a day. Potions shouldn't be any different. Chugging an entire belt of potions could have the same impact as someone downing an entire bottle of pills, and washing it down with a fifth of booze.

This changes potions into planning and gambling. Each potion consumed before a fight means one less healing potion that can be consumed after the fight. It becomes more important to have access to better and stronger potions, since you can't match an Improved Healing Potion by slamming three lesser healing potions in a row. Potion variety also increases in importance, since it is easy to allow the use of a small number of potions at the same time, if they're different potions. Consuming a Lesser Healing Potion and a Potion of Lesser Regeneration would be more acceptable than two lesser healing.

The cost - each potion consumed past the first requires a constitution/body check, and failed checks can lead to paralysis, catatonia, coma, permanent physical and mental flaws, or death

2. Reduced efficiency over time

Like drugs and alcohol, a person can build up a tolerance to potions, requiring stronger and stronger potions to get the same effect. Drinking a bunch of potions in quick succession makes this effect worse, so that a potion-sauced character might have to drink four or five healing potions to get the same effect as two regular potions.

The solution for this is for more expensive and more effective potions, with the players sinking more time and coin into Greater Healing Potions, Miracle Potions, and the like rather than have a bandolier of basic healing potions. Another take is turning said potions into strategic assets in a dungeon campaign, instead of a video game chug'a'lug consumable. 

3. Unexpected Potion Interaction

Again like booze and pills, potions shouldn't exist in isolation. Quaffing a healing potion and a mana potion in the same scene/fight might keep the player spell slinging and sword swinging, but then comes the irritable bowel syndrome. Ah, mate, its just the dungeon trots, a few too many potions and it makes your guts loose and grumbly. Or it causes migraines, or hair loss, or erectile dysfunction. 

Just watch any of the 300 pharma ads you see in a regular day and grab some of those side effects and add it to the player's most abused potion. 

4. Potion Addiction

Having a potion that restores health or mana seems like something ripe for social abuse, who needs miracle cures, superfoods, fad diets, or any of the rest when a healing potion a day... and then natural healing abilities start to fail. A mana potion as a mental booster, fantastic, until going too long leaves the juicer trembling and sweating.

5. Long Term side effects

Also touched on a little bit above, long term use and abuse of any potion could have serious long term side effects, like potion of strength consumers developing emotional or rage disorders, healing potion junkies bodies start to fall apart if they don't keep downing the red stuff because their body has forgotten how to heal itself naturally. 

6. Potion rejection 

Potions are alchemical semi-magical creations and downing one shouldn't really be as quick as easy as shotgunning an ice cold Natty Lite on a boat at the lake over 4th of July weekend. With stronger potions the drinker might need to make a body/system check to see if they can handle the load of chemicals and monster extracts they just gulped down. Might be fine, might be queasy, might violent puke it all back up, might even have an even more violent reaction.

7. Potion Allergy

The mana potion was made with unicorn horn? I'm allergic to unicorns     *dies*