[Clinical study on ligustrazine in treating myocardial ischemia and reperfusion injury]. 
To explore the protective effect of Ligustrazine in treating myocardial ischemia, and reperfusion injury.  The activities of serum superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and lactic dehydrogenase (LDH) and the amount of malondialdehyde (MDA) as well as the effects of Ligustrazine (LGT) on them were determined in 16 patients with cardiopulmonary bypass, who were, scheduled for elective cardiac surgery, were randomly divided into control group and LGT group.  Ligustrazine was given by intravenous drip within 2-3 minute with a definite speed before occlusion and immediately after release respectively.  Their venous blood samples were collected to measure the serum levels of SOD, GSH-Px, LDH and MDA by biochemical methods before the occlusion of aorta, at 30 minutes of occlusion and at 30 minutes after release respectively.  There were significantly and very significantly differences between the values of control group and LGT group.  LGT could effectively protect the myocardium from ischemia and reperfusion injury.