Marsupial milk has been found to be high in fats, protein and ash compared to eutherian milk. The generally low lactose content of marsupial milk and the corresponding low intestinal lactase activity of pouch young marsupials, when considered with the incidence of diarrhoea and the occasional formation of cataracts in orphan kangaroos fed on cow's milk (which has a high lactose content), suggests that a lactose-free milk be fed to orphan marsupials. Of the lactose-free milk substitutes for children now available, it is recommended that Pregestimil, Glucose Nutramigen and particularly CFI be used for very young orphan marsupial herbivores (especially kangaroos), as these are both lactose- and sucrose-free. Isomil, Prosobee and Triglyde, containing sucrose, may be suitable for older kangaroos which are also ingesting solids and brush-tailed possums of all ages. The appropriate natural diet of the orphan marsupial should be available at the time when initial solid food ingestion would occur in the natural state. It is suggested that milk substitute continue to be given until the orphan animal reaches the age where, in the natural state, it would be full independent.