Veritaserum

Veritaserum is a powerful Truth Serum that is most commonly used in interrogation. The potion effectively forces the drinker answer any questions put to them truthfully. Use of the potion is strictly controlled by the Ministry of Magic.

Veritaserum is clear, colourless, and odourless and is almost indistinguishable from water. It can be mixed with any drink, and three drops are a sufficient dose to make the drinker spill out their innermost secrets. It can be resisted through different methods, including Occlumency. According to Severus Snape, the potion must mature for a full lunar phase, and is quite difficult to produce.

Veritaserum was used on Barty Crouch, Jr. in June 1994, when Albus Dumbledore discovered that Crouch was disguised as the Defence Against the Dark Arts teacher, "Mad-Eye" Moody. Severus Snape also threatened Harry Potter with it in the same year, suspecting that Harry had been stealing supplies necessary to brew Polyjuice Potion prior to the discovery that Barty Crouch Jr. was the one who stole the ingredients. Dolores Umbridge attempted to use it on Harry, but to no effect, (apparently because Snape had presented her with a fake potion) and beacuse Harry only pretended to drink it.

Behind the scenes
The name comes from the Latin veritas ("truth") plus serum.

Appearances

 * Harry Potter and the Goblet of Fire
 * Harry Potter and the Half-Blood Prince