Background: Various kinds of sensitizers are administrated foralopecia areata treatment. The aim of this study was to evaluatetreatment response to Dinitrochlorobenzene (DNCB) in alopeciaareata patients.Method: In this study, 117 patients were treated with DNCBunder a specific checklist. All patients were sensitized with a 2%DNCB and then treated with ascending DNCB concentrations(0.001%-2%). Response to treatment was categorized as none,mild, moderate and marked improvement.Result: Thirty three (27.5%) patients showed no response, 49(40.8%) had relapse 6 months after improvement, 29 (24.2%)had no relapse 6 months after the treatment and 6 patientswere excluded because they did not return for follow-up visits.Response to treatment in patients without eyelash and eyebrowinvolvement increased significantly (P=0.01). We did not observeany side effects except for localized dermatitis seen in 5% of thepatients.Conclusion: With respect to the suitable response to DNCBapplication and its availability, the authors suggest that DNCBbe reconsidered in alopecia areata. However, attention must bepaid to its mutagenicity..