A 5-year retrospective study of bone marrow reports was conducted to identify dogs with acute marrow stromal injury. Of 382 reports that were included in the study, acute stromal alterations were identified in 27 (7.1%). Disease conditions associated with these inflammatory changes included nonregenerative immune-mediated hemolytic anemia (IMA), systemic lupus erythematosus, immune-mediated thrombocytopenia, infectious diseases, drug treatments, and idiopathic conditions. Pathologic changes associated with acute stromal injury included coagulation-type necrosis, individual cell necrosis, dilated sinusoids, interstitial edema, hemorrhage, multifocal fibrin deposits, and multifocal neutrophilic infiltrates. Nonregenerative IMA tended to be associated with individual cell necrosis and evidence of vascular injury and acute inflammation. Infectious diseases tended to be associated with coagulation-type necrosis vascular injury and acute inflammation. Microabscesses were observed only in dogs with bacterial infections. Acute stromal injury associated with drug treatments were associated with coagulation-type necrosis but not with vascular injury or acute inflammation. The pattern of these changes may be useful in suggesting possible causes.