"The talented sorceress Tissaia de Vries is credited with discovering this powerful potion, which won her considerable renown. The potion improves the imbiber's vision and allows opponents to be detected even through walls."
De Vries' Extract potion makes concealed creatures visible.
- Formula for De Vries' Extract
- Receiving this potion from the druids in Chapter V, during "The Green March" will unlock the formula if you did not have it already.
- In Berengar's notes on the Beast, it is suggested that with the help of a potion (probably De Vries' Extract), one might be able to see the Beast. This, however, is not really true. The potion does allow Geralt to "see" the beast seconds sooner than he would otherwise in the "non-final" encounters he has randomly with the hound at night. Also, the beast does initially have a blue circle under him, so it seems like dialogue would be possible, but then it disappears as always. In the final encounter, the beast appears before the cut scene even ends, so the potion would be useless.
- Geralt can find De Vries' Extract as an unknown potion on one of the mangled corpses near the Clay Pits in Chapter II.
- Triss Merigold gives the potion to Geralt in Chapter III, before he is sent to retrieve Alvin from the hospital.
- Note that there are actually no invisible creatures in the game.
- De Vries' Extract allows Geralt to locate a Giant Centipede when it is underground. He can still not target it while it is underground, so it is no better than simply pressing the alt key to show object names. It does not show enemies that have not yet been created in the game world, such as Necrophages before they erupt from the ground.