Forgetting Potion

• Type: Potion
• Effect: Causes an unknown degree of memory loss in the drinker.
• Known Ingredients: Unknown from the novels. (See Behind the Scenes)
• Difficulty: Taught to first-year students at Hogwarts School of Witchcraft and Wizardry. It is also a topic on the Potions section of the Ordinary Wizarding Level (O.W.L.) exam.

The physical properties of the Forgetting Potion, such as its color, consistency, or scent, are not described in the original novels.

The primary and sole known function of the Forgetting Potion is to erase memories from the mind of the person who consumes it. The precise scope of the memory loss—whether it erases specific events or a broader range of recollections—is not specified in the canon. It is functionally similar to the Memory Charm (Obliviate), a spell that achieves a similar effect. However, the Forgetting Potion requires brewing and ingestion, whereas the Memory Charm is cast with a wand.

The Forgetting Potion is introduced early in the series as a fundamental part of the Potions curriculum at Hogwarts.

• During Harry Potter's first Potions class, Professor Severus Snape attempts to humiliate him by asking him to describe the potion, a question Harry cannot answer (Harry Potter and the Philosopher's Stone).
• In Harry Potter and the Order of the Phoenix, a question about the composition and use of the Forgetting Potion appears on the theory portion of the Potions Ordinary Wizarding Level (O.W.L.) examination.

Despite being part of the standard curriculum, the Forgetting Potion is never shown being brewed or administered to a character within the seven novels. The most prominent instances of magical memory erasure involve the Memory Charm (Obliviate), famously used by Gilderoy Lockhart and by Ministry of Magic employees to modify the memories of Muggles.

• In the Harry Potter and the Chamber of Secrets video game for the Game Boy Advance, Professor Snape tasks the player with collecting ingredients for a Forgetting Potion. The ingredients listed are Lethe River Water, Valerian Sprigs, Mistletoe Berries, and Standard Ingredient (video game).
• The ingredient “Lethe River Water” is a direct reference to Lethe, one of the five rivers of the underworld in Greek mythology. Drinking from the River Lethe was said to cause complete forgetfulness, a direct parallel to the potion's effect.