The beta-adrenoceptor blockers propranolol, PhQA33 and LB-46 exhibited appreciable activity against tremorine-(TMN) and oxotremorine-(OTMN) induced tremor, whereas pronethalol, (+)-H56/28, (-)-H56/28, Kö-592 and L(+)-INPEA possessed weak action. The two beta-blockers, namely D,L(+/-)-INPEA and D(-)-INPEA acted as weak tremorgens. None of the above compounds suppressed the induced peripheral cholinergic phenomena; or possessed any central anticholinergic activity, as they were unable to afford protection against physostigmine-induced death. Propranolol, PhQA33 and LB-46 antagonized TMN-induced hypothermia and analgesia, but were inactive against OTMN-induced changes. A correlation of the beta-blocking and anti-tremor activity of these agents is unlikely.