Caustar

Caustar is a yellow cream made from poisonous herbs and is often used by mercenaries in combat. Once the poison has entered the body it causes an intense pain, not fatal though.
A creature subjected to this poison must succeed on a DC 11 Constitution saving throw or take 7 (3d4) poison damage and be poisoned for 1d6 minutes. Damage cannot reduce the creature's hit points below 1 hp. As soon as the poison no longer acts, the creature recovers 1 hit point per round.