An agent that stimulates either innate or acquired immunity. In the U.S., immunotherapy is relegated to experimental medicine, but a number of plant substances are used in Europe as immunostimulants. The presumption of immunostimulation is that you increase native resistance and let it run its course. American Standard Practice, with all good intentions, tends to aggressive procedures, and feels empowered only when intervening against, not with, physiologic responses. Medicine is the only approach to many problems, but in the U.S. we all tend to forget that our brand of standard practice is uniquely aggressive and invasive amongst the industrialized nations. There are other ways...which is presumably why you are using this glossary in the first place.