"I can make anything as long as I understand the components of the start and end product. And I can't make anything that takes a greater amount of material than what I can put in, it has to be an equivalent exchange."

So, really, there are a lot of limitations for alchemy. The primary one being that the alchemist has to understand what is being done on an expert level.

[ooc: Sorry for the wait, I was out of town at a wedding.]