La reine fabriqua minutieusement un breuvage secret à partir de fleurs et d'herbes avec un art consommé, et elle obtint un philtre d'amour tel qu'aucun homme au monde qui en boirait ne pourrait, tant qu'il vivrait, s'abstenir d'aimer la femme qui en boirait avec lui.

Tristrams Saga, traduction par Daniel Lacroix.

The queen, meticulously, made a secret beverage from flowers and herbs, and she obtained a love philter such as no man in the world who would drink it could, of his life, refrain from loving the woman who would drink with him.

The most famous philter is of course the love philter. The legend of Tristan and Iseut tells that somewhere between Ireland and Cornwall, Iseut's maid gave the young people a philter intended for the old King Marc and his future wife. Iseut married the king for political reasons but her heart and her thoughts were to belong to Tristan forever.