A 71-year-old woman with icterus was treated with doxycycline orally for one week. She then was admitted for an exploratory laparotomy under general anesthesia with barbiturate, pancuronium, fentanyl, and nitrous oxide. She developed rapid atrial fibrillation and received digitoxin and beta-blockade. Thirty minutes after her last medication she received doxycycline 100 mg in 200 ml sodium chloride 0.9% infused over five to ten minutes. Soon after the completed infusion, she developed a severe anaphylactoid reaction with bronchospasm, hypotension, and generalized urticaria, which was treated successfully with ephedrine, aminophylline, hydrocortisone, furosemide, metaraminol, ketamine, and epinephrine. The possibility of beta-blockade treatment worsening the reaction is discussed and five other reports of anaphylactoid reactions to intravenous doxycycline are mentioned.