1. The effect of beta-adrenoceptor agonists and antagonists on gastric emptying of a solid meal labelled with Indium113m was measured by a gamma camera in healthy volunteers or patients with hypertension. Each subject acted as his own control. 2 In ten subjects given isoprenaline (10 or 20 mg) sublingually 30 min before the meal, gastric emptying half-times were significantly prolonged (P less than 0.05). No effect was observed when isoprenaline was given immediately before the meal. 3 Salbutamol, 4 mg four times daily for 1 week also significantly prolonged gastric emptying in four subjects (P less than 0.05). 4 The effect of isoprenaline on gastric emptying was blocked by propranolol 40 mg four times daily for 1 week. 5 In ten subjects propranolol 40 mg four times daily alone for 1 week was found to significantly speed up gastric emptying (P less than 0.005), suggesting that emptying of the normal stomach is subject to some degree of adrenergic inhibition.