Potions are an adventurer's best friend, but it's not always sensible—or realistic—to carry several dozen potions at once. When you need to carry a lot of potion in a little container, use a flask.
This chapter introduces potion flasks and rules on how to use them in your campaign.
A flask is a small, magically-infused bottle (or other container) that can safely hold a large—but uncertain—amount of consumable potion (or other liquid).
Unlike potions, which typically come in single-use vials, it's always hard to tell exactly how much liquid remains inside a flask—you never quite know how many uses you'll get before it's all gone.
Flasks can vary in appearance based on who crafted it, what it is made from, etc. To see what your flask looks like, roll on the Flask Appearance table below.
Instead of tracking individual drinks, flask quantity is measured with a die—d8, d10, d12, etc. This is your Flask die—roll it whenever you take a drink from the flask: if you roll a 1 or 2, the die gets one size smaller:
If you roll a 1 or 2 on a d4, that's it—the flask is now completely empty until you can find a way to refill it.
d20 → d12 → d10 → d8 → d6 → d4 → 0
|Quantity||Average Uses||Cost to Buy|
|d20||30||22 x base potion cost|
|d12||20||15 × base potion cost|
|d10||14||10 × base potion cost|
|d8||9||6 × base potion cost|
|d6||5||3 × base potion cost|
|d4||2||1 × base potion cost|
There are three common ways to gain a flask: find one on your adventures, buy one from a merchant, or—if you have the right tools and training—create one yourself.
You may find a magical flask on your adventures—in the ruins of a wizard's tower, on the corpse of a dead explorer, in the locked chest of a rich merchant—or be awarded one as a reward for some heroic deed.
Flasks are a rare item that—depending on your setting—may hard to find. But if you can find a vendor selling flasks, an empty flask is a small item that costs 5 gp.
The cost of a partially-filled flask will depend on its quantity and contents—see the Average Uses & Costs table for an exact breakdown.
Valiant wants to buy a flask of lesser healing with d6 quantity. One potion of lesser healing costs 50 gp, so the flask will cost him 150 gp (3 x 50).
This flask contains d6 drinks of potion of lesser healing. When you take a drink, roll a flask die—if you roll a 1 or 2, the flask quantity gets one size smaller.
If you are able to craft magic items, you may craft your own flask—if you can find the right materials.
|2||Spellsealed glass||Rare, glass, force|
|1||Elderspiral wood||Uncommon, wood, force|
If you have an empty flask and are proficient with an alchemist's kit, you can fill an empty flask yourself by combining together potions of the same type and pouring them safely into the flask. This can be done during a short or long rest.
If you don't have the requisite tools or experience, you'll need to find a trained alchemist to perform this service—pouring any ill-prepared potions into a flask will spoil the mixture, nullifying any magical properties.
|Potions Used||Flask Quantity|
Potions are volatile and don't like to be mixed. If you pour any potion—even one of the same kind—into a partially-filled flask, the contents immediately spoil and lose all magical properties.
If you want to allow players to mix potions in flasks but with some volatility, roll a d20 on the table below whenever potions are mixed in a flask. This roll should be done in secret—the player does not notice any change without first making a successful identifying action.
|1-5||The contents lose their original properties and become a potion of poison.|
|6-16||The contents are spoiled and lose all magical properties.|
|17-19||No change in the contents.|
|20||The contents lose their original properties and gain the effect of the newly-added liquid.|
If you are proficient with an alchemist's kit, you can top-up a partially-filled flask during a short or long rest if you have enough potions. As a proficient alchemist, this does not risk spoiling the contents of the flask.
|Flask Quantity||Potions Needed|
|d4 → d6||+2|
|d6 → d8||+3|
|d8 → d10||+4|
|d10 → d12||+5|
|d12 → d20||+7|