If you are refering to the skill, whell you can open your skills window (button under your portrait) and by placing the crusor on a skill you will have the description. The alchemy skill I assume you have, permits you combine portions thus create biger bottles of portions or combine two different portions and get one health portion. I would suggest for you to check all the skills you have invented points and see what you have. Then if you could please inform us which skills you have and what class your char is (mage, warrior etc).