The hero in the play is given a magic/love 'potion' so that he will fall in love with the princess.
He drank the fatal 'potion'.
sleeping 'potions'
(..) Hmm. But that is impossible. Why? You don't need powders and potions, my queen. You don't need lies. You are strong enough to look into the Lord's light and see his truth for yourself. (..)2014 TvShow: Game of Thrones Title: Mockingbird Season: 4 Episode 7
(..) to the truth. If they're lies, my lady, aren't they best avoided? Not always. Most of these powders and potions are lies. Once they step into his light, they will see the lie for what it was-- a trick that led them to the truth. (..)2014 TvShow: Game of Thrones Title: Mockingbird Season: 4 Episode 7