If you randomly poll 100 people for their best meatloaf recipe, you're likely to come up with 100 variations. Some recipes call for onions, some contain ketchup, some oregano, and the list goes on. Yet once the meatloaf is made, you'll still recognize it for what it is. The same goes for anesthesia. Ask 100 anesthesia practitioners about their preferred approach to any given case, and chances are you'll get just as many answers. In the end, however, the result is recognizable as anesthesia care. Unfortunately, these variances can be a source of confusion for non-anesthesia personnel who may be looking to standardize anesthetic agents or, conversely, justify a varied inventory. To help you better understand the art and science of anesthesia, here is a broad-brush review of the three common categories of ambulatory anesthetics.