orange juice = healing potioncoffee = poison
Hot coffee=more pain=pwnt. QED
I don't think coffee's poison. It's just bitter and yukkuris don't like bitter stuff.
PS: the arrows says "Coffee (Black)".
Well, the Selfish Mother Reimu series shows coffee as harmful; although it doesn't actually hurt them, per se, it makes them sluggish, keeping them from hopping -- or even crawling at their normal speed.
1.SFX: GORO GORO GORO (tumble/roll)
2.SFX: DON (thud/wham)
3.SFX: Gura.. (wobble)
4.SFX: BASHA (splash)
5.Arrow: Coffee (black)