Provided is an injectable anthelmintic formulation of eprinomectin. A preferred formulation comprises at least 1.5% w/v eprinomectin, benzyl alcohol, sorbitan monooleate, a vegetable oil or derivative and one or more co-solvents. Further provided is a method of treating cattle by injecting an animal at an injection site, at or near the rear of the animal with the formulation, and a method of treating a herd of cattle, with each animal being treated in a milking shed, by injecting an animal, at or near the rear of the animal with the formulation, whilst the animal is in a bail in the milking shed.
