A depressed or biphasic T-wave electro-cardiographic changes can be observed inrats 24 hours and 4 days respectively afterisoproterenol injection.11 out of 15 of suchanimals receiving Leonurus heterophyllusSweet（L.H.S.）injections show remarkableimprovement or recovery one hour afterdrug injection.20 rats of the control groupreceiving 5% glucose or normal saline rem-ain unchanged.A group of another 10 ratswith elevated T wave changes 24 hours af-ter isoproterenol injection is subjected on the1st

4th

7th day respectively injections ofL.H.S.or normal saline.During this per-iod the L.H.S.treated group improves ra-pidly and steadily and is in sharp contra-distinction to the ineffective normal salinegroup.Our laboratory data reveal that L.H.S.can improve coronary circulation

reduceheart rates and restore the disturbed mesen-tery microcirculation to normal.The electro-cardiographic changes correlate well withthat of microcircnlation.A definite inhibit-ory action of L.H.S.on ADP induce bloodplatelet aggregation is also shown in our invitro experimental study under phase con-trast microscopy.