In my Dream World I am a Potions Master. It's the highest rank a witch or wizard can achieve while studying potions. In this world, I have a PhD in Chemistry, and a Masters in Pharmacology.
I brew all of my own Potions using ingredient substitutions from this world, and whatever the Dreams see fit to provde me. I have a wide range of books from my Dream World as well, and have spent quite a deal of time researching complementary ingredients as well as adequate substitutions.
The side effects are few. Headache, nausea, drowsiness, weakness in the limbs. They are unlikely, though the possibility is there.