Benomyl generates ROS in human bronchial epithelial cells 16HBE14o−. Benomyl upregulates asthma-related proteins, ADAM33 and ORMDL3. Antioxidants alleviate the effects of benomyl exposure in 16HBE14o− cells. Metalloproteinases and cytokines involved in asthma pathogenesis could be proposed as downstream pathways of ORMDL3 overexpression by benomyl.