Anaphylaxis or Type I hypersensitivity reactions in cattle can result in an atypical interstitial pneumonia. The lung is a major target organ in cattle for Type I hypersensitivity. Clinical signs are those of acute respiratory distress. Cattle that die of anaphylaxis may have lesions consistent with those described for atypical interstitial pneumonia. Emergency administration of epinephrine may be needed; supportive care includes anti-inflammatory treatment with corticosteroids or NSAIDs. If pharyngeal or laryngeal edema is present, a tracheostomy may be indicated.