Objectives In the theory of Korean medicine, rice straw (RS) has been used effectively as treatments for dyspepsia, diarrhea, enteritis, inflammatory epigastric diseases and various dermatitis. However, the theory has not been studied intensively yet about anti-inflammatory effects for human. This study was to investigate effects of RS for a treatment of allergic contact dermatitis (ACD) induced by 2,4-dinitrochlorobezene (DNCB) in mice. Methods In this experiment, effects of RS were investigated on changes in body weights, dorsum skin thickness, clinical aspects on the dorsum skin, spleen and body weight among these four groups; normal group (NOR), control group (CON), RS spread group (RSS) and RS spread and administer group (RSS+Adm). In addition, the effects on proliferations of splenocytes were also investigated in vitro and in vivo study. Results RSS group and RSS+Adm group showed increasing in body weights, diminished dorsum skin thickness and treated dermatitis on dorsum skin. In RSS+Adm group, spleen weights were lowered significantly compared to CON group. Conclusions In conclusion, these data suggest that RS can decrease symptoms of ACD significantly, and it shows the anti-inflammatory and immunosuppressant effect as well. Therefore, RS can be useful to treat patients with ACD.