Objective: To observe the effect of different dosages of ligustrazine (LG) on the level of plasminogen activator inhibitor-1 (PAI-1) activity in patients with type 2 diabetes mellitus.Methods: Ninety cases of type 2 diabetes mellitus inpatients were selected

and randomly divided into LG small dosage group (SDG)

LG large dosage group (LDG) and control group. The 120 mg LG

400 mg LG and normal saline 250 ml were given through intravenous dripping respectively

once daily

20 days as one treatment course. Before and after treatment

all the patients had their fasting blood taken for PAI-1 and tissue plasminogen activator (t-PA) assessment test to perform the comparative study.Results: Seventythree out of the 90 patients completed the observation course

the PAI-1 activity of three groups after treatment all lowered compared with that before treatment

and the difference between groups was also significant (allP < 0.01). After treatment the PAI-1 level of SDG and LDG of LG were all markedly lowered (allP < 0.01)

the LDG’s lowering was more evident than that of SDG

and comparison between these two groups of patients showed significant difference (P < 0.01). Although in the control group there was some difference between before and after treatment

it was not so significant like the above-mentioned two groups (P = 0. 0140). No adverse reaction occurred in the 3 groups during the observation period.Conclusion: LG could safely and effectively lower type 2 diabetes mellitus patient’s plasma PAI-1 activity level

and LDG of LG proved to be particularly effective.