OBJECTIVE: To report 2 cases of hypersensitivity reactions associated with oxaliplatin treatment in Asian patients. CASE SUMMARIES: A 33-year-old Chinese woman received adjuvant oxaliplatin in combination with fluorouracil and leucovorin. Shortly during her sixth infusion, she developed a severe hypersensitivity reaction. Despite prophylactic measures, she developed another reaction of similar severity during her subsequent infusion and was not further rechallenged with oxaliplatin. The second case involved a 45-year-old Malay woman who received oxaliplatin, fluorouracil, and leucovorin for metastatic colorectal cancer. Shortly during her ninth infusion, she developed a mild hypersensitivity reaction. With prophylactic measures, she developed less marked reactions with her subsequent 3 infusions. DISCUSSION: Hypersensitivity reactions to oxaliplatin have been reported to be between 12% and 16% in the Western population. As of April 20, 2005, there are only 2 previously published reports of hypersensitivity reactions to oxaliplatin in 6 Asian patients. The incidence rates of such reactions in different Asian ethnic groups could vary. The cumulative dose, time of exposure to oxaliplatin, and clinical features were variable and unpredictable in all of the reported Asian patients who developed hypersensitivity reactions. An objective causality assessment using the Naranjo probability scale revealed that oxaliplatin was the highly probable cause of hypersensitivity in the 2 Asian patients reported by our center. CONCLUSIONS: Patients who develop mild to moderate reactions can be rechallenged with the drug administered as a slow infusion with prophylactic measures. Desensitization may allow patients who experience severe hypersensitivity reactions to oxaliplatin to further receive effective therapy for their colorectal cancer.