A series of aporphines and oxoaporphines was tested for antiplatelet and vasorelaxing actions. (+)-N-Methylactinodaphnine, (-)-norannuradhapurine . HBr, xylopine, actinodaphnine, and N-methylnandigerine showed strong inhibition of adenosine 5'-diphosphate (ADP)-induced platelet aggregation. Boldine, (+)-N-methylactinodaphnine, (-)-norannuradhapurine . HBr, xylopine, N-acetyllaurolitsine, N-methyllaurotetanine, abinodaphnine, N-methylnandigerine, O-methylbulbocapnine, and liriodenine showed strong inhibition of arachidonic acid (AA)-induced platelet aggregation. (+)-N-Methylactinodaphnine, fissoldine . HClO4, (-)-norannuradhapurine . HBr, xylopine, N-methyllaurotetanine, actinodaphnine, N-methylnandigerine, O-methylbulbocapnine, and liriodenine showed strong inhibition of collagen-induced platelet aggregation. (-)-Norannuradhapurine . HBr, xylopine, N-methyllaurotetanine, and actinodaphnine showed strong inhibition of platelet-activating factor (PAF; 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine platelet aggregation. (+)-N-Methyladinodaphnine, laurotetanine, N-methylactinodaphnine N-oxide, oxoglaucine, boldine, and actinodaphnine showed vasorelaxing action in rat thoracic aorta. The results are discussed on the basis of structure-ability relationships.