Troll oil
From Vanathul Wiki
Using troll blood harvested at great peril in the forests bordering the Verdant Veil, Troll Oil is one of the many products using the regenerative properties of the blood to treat wounds.
Troll Oil is often a byproduct separated out when brewing a Troll styptic, but is at times also made directly.
Price 50 gp; Weight 1 lb.
This crimson liquid is viscous and tastes foul. If you drink it, for the next hour you automatically stabilize when reduced to negative hit points (unless the damage is sufficient to instantly kill you) and have a 50% chance each round to end any bleed effect on you. If you take fire or acid damage, the benefits of troll oil are suspended for 1 round.