Annatto is a low, fast growing tree, also called "achiote" in Spanish. Its arrowhead shaped seed pods contain numerous seeds covered with a bright red-orange aril. The coloring material (bixina) around these seeds is a common natural food color used around the world, especially to color margarine.
The main use of annatto is for digestive and stomach problems, for hypertension, for infections of the prostate and urinary tract, to lower cholesterol and topically against skin, ear and eye infections.
See the Raintree link below for far more information.