Fee Brothers came into being in 1863 when the second generation Irish immigrant Fee family opened up a grocery and liquor store under the management of 25 year old James Fee. The operation expanded over the years to importing and bottling wine became popular in the latter part of the 20th century as a maker of cocktail mixers. The business has been relabeled and reborn in the 1990s and is now expanding its product line of mixers and bitters.
Fee Brothers Aztec Chocolate Bitters is a very lightly proofed bitters ingredient for cocktails. Oddly, this is not currently (as of October, 2011) acknolwedged on their website. Various sales sites describe it as blend of cocoa and "heat" (spice).