A potion of full healing will heal up to 400 HP. If you would gain more HP than your maximum, a blessed potion will also increase your maxhp by 8, and an uncursed potion will increase it by 4; a cursed potion will not increase your maxhp. The potion will also cure hallucination and blindness, and exercise constitution and strength, and if not cursed, will cure sickness. If you have lost experience levels, a blessed potion will also return one, but you cannot gain more than half of the lost levels this way. You can throw this potion at Pestilence or hit him with it to deal damage to him.