Abstract: MENG Chen-yang *, CHEN Hong-guang, MENG Xiao-yin, XING Wei-bin, FU Guo-jun. *Hebei Cangzhou Medical College, Cangzhou 061001, Hebei, China Corresponding author: FU Guo-jun, Email: Fgj8899@163.com 【Abstract】 Objective To evaluate the therapeutic effect of hydrogen-rich saline on allergic contact dermatitis （ACD） in mice and to explore its underlying mechanisms. Methods Forty mice were equally divided into 4 groups: control group, control treatment group, ACD group and ACD treatment group. ACD was induced by repetitive topical application of dinitrofluorobene（DNFB） to the left ear of mice on day 1, 2 and 5. Hydrogen-rich saline was intraperitoneally given to the mice in the ACD treatment group at a dose of 5 ml/kg per day from day 1 to 5. On day 6, the mice were sacrificed, ear tissue was removed from them and subjected to measurement of thickness and weight, detection of tumor necrosis factor （TNF）-α, interleukin （IL）-6, IL-17 and interferon （IFN）-γ expression by enzyme linked immunosorbent assay, as well as numeration of inflammatory cells in lesions after hematoxylin-eosin （HE） staining. Data were processed by SPSS 18.0 software, and statistical analysis was carried out by one-way analysis of variance and least significant difference （LSD） procedure. Results Compared with the control group, the ACD group showed a significant increase in lesion score （7.33 ± 1.53 vs. 0, P < 0.05）, differences in the thickness （（0.73 ± 0.15） mm vs. （0.13 ± 0.05） mm, P < 0.05） and swelling degree （expressed as tissue weight: （18.67 ± 3.05） mg vs. （3.33 ± 1.52） mg, P < 0.05） between the left and right ear, expressions of TNF-α（（1475.52 ± 233.81） pg/mg vs. （239.01 ± 52.39） pg/mg, P < 0.05）, IL-6（（184.65 ± 78.39） pg/mg vs. （42.28 ± 17.64） pg/mg, P < 0.05）, IL-17 （（628.56 ± 201.44） pg/mg vs. （127.58 ± 50.28） pg/mg, P < 0.05） and IFN-γ（（197.72 ± 37.81） pg/mg vs. （24.57 ± 8.31） pg/mg, P < 0.05）, and the number of inflammatory cells per square millimetre in the left ear tissue （752.00 ± 166.06 vs. 127.33 ± 77.18 , P < 0.05） . However, hydrogen-rich saline treatment induced a statistical decrease in all of these parameters in the ACD treatment group compared with the ACD group, including lesion score （3.33 ± 0.58, P < 0.05）, difference in thickness （（0.46 ± 0.11） mm, P < 0.05） and swelling degree （（11.00 ± 2.64） mg, P < 0.05）, expressions of TNF-α （（817.72 ± 101.13） pg/mg, P < 0.05），IL-6 （（95.86 ± 36.65） pg/mg, P < 0.05），IL-17 （（373.38 ± 126.74） pg/mg, P < 0.05）, IFN-γ （（63.31 ± 17.38） pg/mg, P < 0.05） and the number of inflammatory cells per square millimetre（384.00 ± 97.35, P < 0.05）. Conclusion Hydrogen may inhibit the release of inflammatory factors in ACD.