<正> A model of irreversible hemorrhagic shock was reproduced in rats andchanges of the microcirculation of the cremaster muscle were recorded by a specialHitachi color TV camera.In the control group（N=12）

1 hour after hypotension（BP 40 mm Hg）

0.6 ml of normal saline was given i.v.

followed by reinfusion ofthe shed blood.In the experimental group

with the same procedure

crystal No4of Polygonum cuspidatum（p.c.）was given in three different dosages

viz 0.5

1.0

and 2.0 mg/100 g b.w.（N=8 for each dosage）.Administration of p.c.andreplacement of the shed blood was associated with a restoration of the narrowedarterioles to near normal dimensions

blood capillary reflow

and a return of bloodpressure to stable normotensive levels.In contrast

in the saline-treated group

blood pressure tended to fall gradually and no complete restoration was observedeven at 2 hrs after treatment.Topical application of p.c.served to dilate thenarrowed arterioles.The 24 hr survival rate in p.c.-treated group（23/24）wassignificantly greater than that in saline-treated group（2/12）.The data show thatp.c.is an effective drug for ameliorating microcirculatory insufficiency andincreases survival rate in hemorrhagic shock animals.