This study aimed to investigate whether enema is associated with nervous system injury caused by diquat poisoning using a population-based case-control analysis. Medical records of patients with acute diquat poisoning admitted to the hospital from January 2018 to January 2024 were retrospectively collected. Central nervous system injury symptoms following diquat poisoning defined the case group, while the control group were matched 1:2 on population-based without nervous system injury in diquat poisoning patients. Conditional logistic regression models were used for analysis. We identified 101 diquat poisoning patients with nervous system injury and selected 202 diquat poisoning patients without nervous system injury. Diquat poisoning patients performed 2 and ≧ 3 enemas had ORs of nervous system injury of 3.084 (95% CI 1.230, 7.734) and 4.693 (95% CI 1.408, 15.645) compared with diquat poisoning patients with no enema, respectively. Further analyses were performed in various age subgroups. The ORs of conducting 2 and ≧ 3 enemas were dramatically higher among case group than control group in subgroup aged ≧ 60 years old (OR 10.184, 14.982 respectively). We concluded that enema may be associated with an increased risk of nervous system injury caused by DQ poisoning, particularly among the elderly.