Focal eosinophilic enteritis in horses is an idiopathic disease that can cause acute abdominal pain. It is characterized by infiltration of eosinophils into the equine intestinal tract. Intramural hematoma of the small intestine is also a poorly understood disease. This case report describes a surgical colic in a 9-year-old mare that had jejunal obstruction caused by an intramural hematoma secondary to focal eosinophilic enteritis. Diagnosis was confirmed by histopathological results showing eosinophilic infiltration and subserosal granulomas that contained large numbers of hemosiderin-laden macrophages. Damage to the mucosal barrier of the intestine may have led to an immunologic reaction and subsequent eosinophilic enteritis. While the cause of the eosinophilic enteritis is unknown, our hypothesis in this case was an underlying hypersensitivity such as food allergy may have played a role based on literature and histopathological examination.