The main difference between a natural and artificial flavor is the origin of the flavor chemicals. Natural flavors must be derived from plant or animal material. Artificial flavors are synthesized in the lab. The actual chemicals in these two kinds of flavors may be exactly the same: the chemical structures of the individual molecules may be indistinguishable.
The Food and Drug Administration defines natural flavors as substances derived from animals or plants and artificial flavors are those that are not. An artificial flavor must be comprised of one of the nearly 700 FDA-allowed flavoring chemicals or food additives categorized as “generally recognized as safe,” or any of 2000 other chemicals not directly regulated by FDA but sanctioned for use by an industry group, the Flavor and Extract Manufacturers Association of the United States. Most of these chemicals exist as natural flavors or can be extracted from them.
From a food manufacturer’s perspective, the difference between a natural and artificial flavor often comes down to cost and consumer preference. A natural flavor almost always costs much more than an artificial flavor. Still, food makers are often willing to pay because they know that some consumers prefer “natural” flavors.
Interestingly, the chemical mixtures that comprise artificial flavors are often simpler than “natural” flavors. The reason: artificial flavors contain fewer chemicals than natural ones, which can be mixtures of several hundred chemicals.