philter

philter \FIL-tur\, noun:

1. A potion or charm supposed to cause the person taking it to fall in love.
2. A potion or charm believed to have magic power.
3. To enchant or bewitch with or as if with a magic potion or charm.

Some things you can feel coming. You don't fall in love because you fall in love; you fall in love because of the need, desperate, to fall in love. When you feel that need, you have to watch your step; like having drunk a philter, the kind that makes you fall in love with the first thing you meet. It could be a duck-billed platypus.
-- Umberto Eco, Foucault's Pendulum

Philter is derived from Greek philtron, from philein, "to love," from philos, "dear, loving."