The magnitude of rat-paw oedema induced with serotonin, carrageenin or prostaglandin E1 is decreased to a statistically significant extent with the naturally-occurring procyanidin. In the case of carrageenin-oedema, procyanidin is about twice as effective as phenylbutazone. Procyanidin applied intraperitoneally in doses of 10, 20 or 40 mg/kg, exerted no influence on the blood pressure of rats. When, however, it was injected intravenously, a dose of 35 mg/kg caused a slight decrease in the blood pressure of the anaesthetized animal, while doses of 50-100 mg/kg led to long-lasting reduction of blood pressure.