Metronidazole, a widely used drug for the treatment of infections with anaerobic and facultative anaerobic bacteria and protozoa, can frequently cause metronidazole-induced cutaneous adverse reactions (McADRs). The aim of the present study was to investigate the association between human leucocyte antigen (HLA) alleles and McADRs in a Chinese Han population. The frequency of HLA-B24:02 carriers among the McADR patients was 73.3%, which was significantly higher than that of the population controls (32.16%, OR = 5.80, 95% CI = [1.80-18.72], Pc = 0.004) and of the metronidazole-tolerant patients (26.67%, OR = 7.56, 95% CI = [2.02-28.35], Pc = 0.004). Molecular docking showed that metronidazole and one of its major metabolites had the potential to bind in the HLA groove and that there was a relatively stable binding state of the HLA-B24:02-metronidazole/the metabolite complex. The CDR3 repertoires of both T cell receptor (TCR)Vα and Vβ of the patients showed a significantly skewed or an oligoclonal distribution. The TCRVβ CDR3 of the patients shared a similar motif, "CASSxxxxxxQxF." The current study demonstrated that both the HLA-A*24:02 allele and TCR are involved in the pathogenesis of McADRs.