Several definitions of alchemy exist. Originally, alchemy was an ancient tradition of sacred chemistry used to discern the spiritual and temporal nature of reality, its structure, laws, and functions. Alchemy is often considered a predecessor to the modern science of chemistry.
Alchemy, as the foundation of moderm chemistry, was known as the attempt to turn lead into gold. In reality, the physical science is simply a representation of a spiritual practice. the practicing alchemist is attempting to transmute one's soul from lead, or the impure, to gold, the pure. It is a spiritual undertaking, and the ability to turn lead into gold was (and is) seen as proof of one's oneness with the universe and purity of spirit.
Alchemy was the practice of transmutting one substance into another, or of creating one thing from the combining of other elements. Most famously, this was a quest for turning common metals into gold.
If we define gold as a yellow, soft metal, then yes, alchemy really "existed" and some alchemists were even successful. Mind, they didn't create real gold, just alloys that had the same apperance.
Note, another goal of the alchemist was the creation of an homunculus; that is, the creation of a human-like creature without the use of sexual reproduction. A few alchemists claimed to have been successful, but despite the prestigue such an achivement would have granted not a one ever allowed others to see the creature. Thus, it is believed that they failed misserably on this account
Alchemy is a type of chemistry that doesn't usualy follow the scientific procedure. Used Mainly back in the medieval days. They didn't really use any method at all. Just did hundreds of experiments and rarely wrote anything down and/or took any observations.