Smoking and health are increasingly understood to be incompatible. To evaluate, prospectively and retrospectively, the attitudes of employees, staff physicians, and patients of a medical institution, a questionnaire was administered before and after implementation of a no-smoking policy. Of many questions, select ones reviewed here focused on the following concerns: (1) how tobacco smoke affects employees and patients, (2) employee acceptance of a no-smoking policy before and after its implementation, and (3) the consequences of the policy on employee smokers. Open-ended questions about smoking were constructed by a committee comprised of clinicians, investigators, and administrators. The questionnaire was given to 2,000 randomly selected patients and the institution's entire staff of 4,200 employees and 225 staff physicians. Data were obtained on three occasions: six months before, six months after, and one year after the implementation of the no-smoking policy. The majority of patients, employees, and physicians indicated that the smoke of others bothered them and ranked the following as most offensive: smell, eye irritation, provocation of sinus problems, coughing, and headache. Approximately 80 percent of employees and patients favored the policy before its inception; and employees increasingly favored it through the year after its implementation with a favorable attitude increasing by nearly 10 percentage points. One year after implementation, 80 percent of patients were in favor of the policy. In the final survey, 74 percent of respondents indicated the policy had helped them. One year after policy implementation, employee smoking was reduced significantly from 22 to 14 percent; and of those employees who continued to smoke, 81 percent smoked less than eight cigarettes per day.(ABSTRACT TRUNCATED AT 250 WORDS)