Effect

Potion effects are conferred by food items called Potions, or alternatively a throwable version called Splash Potions, both of which can be brewed using a Brewing Stand in Beta 1.9 Pre-release 3 in order to acquire the effects.

Behaviour
As of 1.9 Pre-release 4, a player affected by a potion effect emits swirly particles for the duration of the effect.

Parameters
Potion effects are given two parameters on creation: Duration (in ticks) and strength.

History
Potion effects were introduced in Beta 1.8. although no potions were added yet so they were used exclusively for in game actions such as sprinting.

In Beta 1.9 Pre-release 2 actual potions were added and some effects got an alchemical ingredient that correspond to them and Milk was given the ability to cure and clear all potion effects.

In 1.9 pre-releases 2 and 3, Ghast Tears were ingredients in Potions of Healing, in 1.9 pre-release 4 they are used in Potions of Regeneration.

In 1.9 pre-release 4 Glistering Melons were introduced, as the new alchemical ingredient for Potions of Healing.