The effects of Abana, an Ayurvedic remedy, administered orally to rabbits was studied for its effects on isolated atria and intestine. Administration of Abana for 3 days increased the basal amplitude and reduced the responses of atria to isoprenaline and norepinephrine. Combined treatment with Abana and isoprenaline reduced this effect. It is possible that Abana treatment for 3 days has an action similar to that of chronic administration of isoprenaline (down regulation of beta receptors). A similar down regulation of beta receptors of smooth muscle of rabbit intestine also seems to occur. Abana pretreatment potentiated the inotropic responses of histamine and CaCl2. These effects may be due to a specific depressant effect of Abana on the adrenergic receptors and a direct sensitization of the atrium manifested by an increased response to CaCl2.