Milk Bucket

A milk bucket is a drink and ingredient obtained from cows or mooshrooms.

Cows and mooshrooms
Milk buckets can be obtained from cows and mooshrooms by pressing while looking at them with an empty bucket.

Wandering trader
A milk bucket has a chance of dropping from a wandering trader, if the trader is killed while holding it.

Usage
Holding with a milk bucket starts the drinking sound and animation. The animation is shown only in first-person camera mode.

When consumed, milk immediately removes any status effects from the player. Drinking milk does not remove the benefits of area status effects granted by Beacons, Conduit Power, or Hero of the Village.

Fire is not a status effect; therefore, drinking milk doesn't extinguish a burning player.

ID
Java Edition:

Bedrock Edition:

Item data
In Bedrock Edition, milk buckets use data value to determine contents. Once used, each data value is set to 0 (Empty Bucket). If no data value is provided, data value is 0.