A questionnaire was sent to physicians with an interest in chest disease to determine the dose and method of delivery of nebulised beta agonists in hospital. All of the 67 physicians replying gave beta agonists by nebuliser, and all reported either salbutamol (72%) or terbutaline (10%) as the drug they prescribed most commonly (18% gave either drug). There was a fivefold difference in the dose of salbutamol they prescribed most commonly (range 2.5-12.5 mg, mode 5 mg), a 20 fold difference in the volume of diluent solution used (range 0.5-10 ml, mode 2 ml), and a 10 fold variation in the flow rates of gas driving the nebuliser (range 1-10 1/min, mode 4 1/min). There are therefore very large variations in the dose and method of delivery of beta agonists nebulised in hospital. Studies attempting to determine the optimum dose of beta agonist for use in a nebuliser need to take the type of nebuliser, diluent volume, and gas flow rate into account.