This is a bottle of agua de vida, the mystical secretions of the baby sandworm. It is said that drinking this will allow you to look so deep into yourself that you will see through yourself, and into the memories of your ancestors.
"Agua de vida", literally "Water of Life" in Spanish, references the water that comes from the dying sandworm, the Water of Life, in Dune. In the novel, the Water of Life is also used to connect to one's ancestral memories.
The image for this item looks like the "medicine" from Zelda II, which is also referred to as the "water of life" in game.