Minecraft wiki entry for Potion, associated text: A potion can reach a maximum tier of 127, but using the /effect command, effect levels can reach 255.
When a player drinks two potions by quickly switching to another potion immediately after drinking one, the second drinking animation is not shown.[verify]
A potion of Poison II lasts for 22.5 seconds, but it is displayed as 22 seconds because the item hover display shows rounded-down integer values.
The "Local Brewery" advancement uses the Uncraftable Potion texture for its icon.