not-yet-known not-yet-known not-yet-known unknown There is a paucity of literature describing equine lipoid pneumonia (LP) caused by inadvertent intra-pulmonary administration of liquid paraffin (mineral oil). This case report improves our understanding of LP by describing; 1) the first reported return of a horse to racing after LP, 2) the likely benefits of prolonged dexamethasone administration, 3) the detailed short- and long-term pulmonary and systemic responses to intra-pulmonary liquid paraffin, and 4) the prolonged pulmonary retention of liquid paraffin.