Bolpian otter oil was a food ingredient, a type of oil from the Delta Quadrant, derived from a sort of otter. This oil was part of the culinary repertoire of the Talaxian traveler Neelix, in particular used to make salad dressing. Neelix recommended a blend of Bolpian otter oil and perjuta vinegar to create a dressing for his version of a Yallitian recipe called crystal salad. (ST reference: Star Trek Cookbook)