Summary of iodinated contrast media (ICM)-induced hypersensitivity. ICM or excipients may activate the basophil or mast cell to release histamine and other mediators, and then induce immediate hypersensitivity reaction (IHR) via IgE-mediated or non-IgE pathways, such as the complement system pathway. Non-immediate hypersensitivity reaction (NIHR) induced by ICM can be evoked by a T-cell mediated pathway. Skin test, basophil activation test (BAT), drug provocation test (DPT), and lymphocyte transformation test (LTT) can achieve the diagnosis of ICM hypersensitivity. In patients with anaphylaxis or severe, prolonged symptoms of NIHR, prompt and appropriate intervention is needed.