Intravenous preparations combining aminophylline and a steroid are used frequently in the treatment of bronchial asthma attacks. However, anaphylactoid reactions to such preparations have been rarely observed. We report the case of a 31-year-old man with aminophylline and steroid allergy. Aminophylline is the ethylenediamine salt of theophylline. In our patient, aminophylline, ethylenediamine and various steroids were found to be positive in the intradermal test. The challenge test with intravenous aminophylline was positive, while that with oral theophylline was negative. Ethylenediamine is used in everyday products such as shellacs and rubber products. In the case of our patient, his asthma worsened following the remodelling of his restaurant. Occupational asthma due to exposure to ethylenediamine is also discussed.