A total of 73 bronchial secretions was obtained by two techniques 40, with the use of tetracaine hydrochloride and 33, with the use of lidocaine hydrochloride anesthetic during bronchoscopy. It was found that only 16 of the 40 specimens resulted in bacterial growth on soy agar medium when the tetracaine hydrochloride technique was employed. All remaining 33 specimens grew well on soy agar with the use of the lidocaine hydrochloride technique. It was shown that probably the inherent chemical property of tetracaine hydrochloride along with other factors was responsible for its inhibiting action on Staphylococcus aureus and Monilia at a concentration of approximately 500 gamma per ml. Approximately 2000 gamma per ml. for S.aureus and 3000 gamma per ml for Monilia were necessary before inhibition was effected with the use of lidocaine hydrochloride. A comparison of prior bronchoscopy sputum specimens, bronchial aspirations, and post-bronchoscopy sputum specimens on the same patients appeared to indicate possible growth inhibition of Mycobacterium tuberculosis in bronchial secretions with the use of tetracaine hydrochloride. It should be apparent from this study that caution must be exercised in evaluating bronchial secretions that are bacteriologically negative on culture by the tetracaine hydrochloride or other similar techniques.