When we think of "potions", we usually think of one-shot items that we ingest, to manifest the stored power within. Unlike scrolls, the user need not be able to read the esoteric inscriptions, inscribed upon the specially prepared parchments, to activate the item's magic. "Potions" also tend to be less powerful than scrolls. In later editions of D&D, potions are equivalent to spells of the 1st to 3rd Spell Level (not the level of the caster). This is a good rule of thumb when deciding how powerful to make new "potion" equivalent items in your campaign.
In our home campaign, we've expanded "potions" into a category of one-shot magic items that are consumed (not necessarily ingested), to take effect. These items can be created by either traditional spell-casters, or alchemists (a semi-NPC-only class). Like traditional potions, they are consumed, applied, crushed, whatever, and expended in one use. All rules that apply to typical potions (duration, etc.) are generally the same for these new items.
You may choose the form of any "potion" found in your game, or roll 1d8 and consult the table below.
- Potion - Typically imbibed
- Ointment/Salve - Usually applied externally
- Drops - Dropped into eyes
- Essence - A "magic cloud" that infuses the user upon release from whatever item it was contained in.
- Biscuit/Cookie/Candy - Any form of edible can be used
- Herbs - Usually eaten, or worn as a charm
- Fumes/Gas - Inhaled
- Powder/Dust - Sprinkled over the user