Abstract Background There have been only few reports on butylscopolamine-induced anaphylaxis despite its global usage as an anticholinergic agent for approximately 70 years. We present a case of anaphylaxis caused by butylscopolamine. Case presentation A 63-year-old woman underwent gastrointestinal endoscopic examination. She developed facial cyanosis and hypoxia after intravenous administration of butylscopolamine 10 mg, and her blood pressure was unmeasurable. Her hemodynamic condition recovered after a total of 0.6 mg adrenaline and bolus administration of 100 mg hydrocortisone. One hour after the onset of hypotension, both plasma histamine and serum tryptase were remarkably elevated to 271.7 nmol/L and 174 μg/L, respectively. Skin tests performed 47 days after anaphylaxis showed a positive result only for butylscopolamine among the exposed agents, which was confirmed by basophil activation tests using CD203c and CD63 as markers. Conclusion Butylscopolamine has the potential to cause severe anaphylaxis; hence, identification of the causative agent is important to prevent recurrence of anaphylaxis.