Donkeys and mules have been gaining popularity worldwide, not only as work animals, but also as pets, for therapy of adults and children with motor or psychologic disorders, sport activities, and for consumption. Pharmacologic information for drugs used in equine practice is scarce for these animals. Thus, clinicians often extrapolate dosing protocols from horses, even when differences have been described. This can result in the wrong diagnosis and treatment, but also on unnecessary expenses. Therefore, species-specific pharmacologic studies for donkeys and mules are necessary. The metabolism for many drugs is faster in donkeys, needing shorter dosing intervals and higher doses, but they can also be more susceptible to some drugs.