Williams (1) and Cooper (2) have published several methods for assigning endotoxin specifications to nonfinished drug ingredients. Thesemethodswill be detailed herein. The first method has been tagged a “control strategy” in that it seeks to estimate relevant limits by which to confine or control potential contaminants. There are cases, especially unique ingredients, that require one to develop relevant levels of endotoxin for targeting specifications. A second method, referred to here as the “strategic” method, is simpler, and may be preferable for well-characterized excipients.