Objective To investigate the role of human cytomegalovirus (CMV) in the occurrence of drug eruptions.Methods Peripheral blood samples were collected from 44 patients with drug eruptions (including 13 severe cases) and 50 healthy human controls.Taqman fluorescent real-time quantitative PCR (RT-PCR) was performed to determine the positive rate and load of CMV DNA in peripheral blood mononuclear cells (PBMCs).Enzyme-linked immunosorbent assay (ELISA) was conducted to detect anti-CMV IgM antibodies in sera.Results The positive rate of CMV DNA was significantly higher in the patients than in the controls (65.91％ (29/44) vs.28.00 ％ (14/50),x2 =13.552,P ＜ 0.05),significantly different among patients with severe drug eruptions (11/13),patients with mild drug eruptions (58.06％ (18/31)) and the controls (x2 =16.153,P ＜ 0.05).In addition,patients with severe drug eruptions showed a higher positive rate of CMV DNA compared with patients with mild drug eruptions (x2 =13.817,P ＜ 0.05) and the controls (x2 =7.237,P ＜ 0.05).CMV DNA load was significantly higher in the patients than in the controls ((28 183.829 ± 19 527.654) vs.(3 019.952 ± 1 760.952) copies,t' =8.517,P ＜ 0.05).No significant difference was found in CMV DNA load between patients with severe drug eruptions ((554 813.389 ± 722 642.498) copies),patients with mild drug eruptions ((13 290.558 ± 14 082.356) copies)) and the controls (P ＞ 0.05).The positive rate of anti-CMV IgM antibodies was similar between the patients and controls (13.64％ (6/44) vs.6.00％ (3/50),P ＞ 0.05),but significantly different among patients with severe drug eruptions (4/13),patients with mild drug eruptions (6.45％,2/31) and the controls (x2 =7.832,P ＜ 0.05),and significantly higher in patients with severe drug eruptions than in the controls (x2 =6.409,P ＜ 0.05).Conclusions CMV infection exists in patients with drug eruptions,and might be a factor associated with the initiation and aggravation of drug eruptions.