With an increasing use of traditional Chinese medicine (TCM) in type 2 diabetes mellitus (T2DM), evidence of long-term benefit with adjunctive TCM treatment is limited. This study investigated whether the concurrent TCM treatment reduces the risk of vascular complications in T2DM patients by using a large population from National Health Insurance Research Database (NHIRD).We identified 33,457 adult patients with newly diagnosed T2DM using anti-diabetic agents from a random sample of one million beneficiaries in the NHIRD between January 1, 2000 and December 31, 2011. We recruited 1049 TCM users (received TCM over 30 days with a diagnosis of T2DM) and randomly selected 4092 controls as the non-TCM cohort at a ratio of 1:4 frequency-matched by age, sex, hypertension, hyperlipidemia, and index year. We investigated the prescription pattern of TCM and conducted a Cox proportional hazards regression to calculate the hazard ratios (HRs) of stroke, chronic kidney diseases (CKD), and diabetic foot between the 2 cohorts.In the TCM cohort, the prescription pattern of TCM was different between insulin and noninsulin patients. The most common herbs were Dan-Shen (Radix Salviae Miltiorrhizae) in noninsulin group and Da-Huang (Radix et Rhizoma Rhei) in insulin group. The most common formulae were Liu-Wei-Di-Huang-Wan in noninsulin group and Yu-Quan-Wan in insulin group. Although no significant reduction in the hazard ratio of CKD and diabetic foot, the incidence rate of stroke was 7.19 per 1000 person-years in the TCM cohort and 10.66 per 1000 person-years in the control cohort, respectively. After adjustment of age, sex, hypertension, hyperlipidemia, and antidiabetes agent use (including sulfonylureas, α-glucosidase, metformin, meglitinide, thiazolidinediones, and insulin), TCM cohorts were found to have a 33% decreased risk of stroke (95% CI = 0.46-0.97; P < 0.05).This population-based retrospective study showed that the complementary TCM therapy might associate with the decreased risk of stroke in T2DM, suggesting TCM as an adjunctive therapy for T2DM to prevent subsequent stroke.