BACKGROUND To investigate the effects of dual plasma molecular adsorption system (DPMAS) on the liver function, electrolytes, inflammation, and immunity in patients with chronic severe hepatitis (CSH). METHODS Total of 162 patients with CSH treated in our hospital from March 2016 to December 2018 were enrolled and equally randomly divided into control group (n = 81) and observation group (n
= 81). The patients in control group were treated with plasma exchange, while those in observation group were additionally treated with DPMAS based on the treatment in control group. The liver function, electrolytes, inflammation, and immunity were evaluated and compared between the two groups. RESULTS After treatment, the liver function indexes in observation group were significantly favorable compared with those in control group, with the reduction in TBIL, DBIL, ALT, and rise of CHE levels (P < 0.05). The levels of K(+) , Na(+) , Cl(-) , and Ca(2+) in both groups were significantly improved after treatment (P < 0.05), although there were no significant differences between the two groups (P > 0.05). The levels of C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) in both groups declined after treatment compared with those before treatment, and those levels in observation group were higher than that in control group (P < 0.05). After treatment, the levels of cluster of differentiation 3(+) (CD3(+) ), CD4(+) , and CD4(+) /CD8(+) were higher in observation group than those in control group, with decreasing level of CD8(+) (P < 0.05). CONCLUSION Dual plasma molecular adsorption system can effectively improve the liver function, effectively correct the electrolyte disorders, reduce the inflammatory response, and adjust the immunity in patients with CSH.