Background: Hemoptysis occurs due to either pulmonary diseases or bronchoscopy interventions. The aim of the present study was to compare the efficacy of the endobronchial instillation of adrenaline with that of tranexamic acid. Methods: Fifty patients were randomly selected as 2 double-blinded sample groups (n=25). In these patients, bleeding could not be controlled with cold saline lavage during bronchoscopy and they, therefore, required prescription of another medicine. Adrenaline (1 mg) in one group and tranexamic acid (500 mg) in the other group were diluted in 20 mL of normal saline and instilled through the bronchoscope. This technique was repeated 3 times at 90-second intervals, if necessary. In the case of persistent bleeding, 90 seconds after the last dose, a second medicine was given for bleeding control. Observation of clot through the bronchoscope meant that the bleeding had stopped. The efficacy of tranexamic acid and adrenaline was evaluated and then compared using the Mann–Whitney test.Results: The time of bleeding control had no significant difference between tranexamic acid and adrenaline (P=0.908). Another analysis was done to evaluate bleeding control with a second medicine; the results showed that 1 (4%) patient in the tranexamic acid and 8 (32%) in the adrenaline group needed the second medicine and there was no significant difference between the 2 groups (P=0.609).Conclusion: Our results suggested that tranexamic acid by endobronchial instillation was as efficient as adrenaline in controlling hemoptysis and required less frequent use of a second medicine.Trial Registration Number: IRCT2014120220188