Background: This review is a continuation of preceding papers on invasive methods applied for diagnostics or drug delivery with questionable clinical indications and/or research purposes. It aims to serve as a reminder that the risk-to-benefit ratio should be kept as low as possible. Methods: Review of literature and Russian patents; author’s observations since 1983. Results: The use of bronchoscopy as a diagnostic and drug delivery method in asthma, bronchitis and tuberculosis is discussed in some detail. Bronchoscopy was applied in children and adults with asthma both during remissions and exacerbations, as well as pre-asthma defined as bronchitis with elements of bronchospasm and allergy. In the pediatric clinic of the Moscow medical academy, endoscopic methods have been applied in children and newborns for diagnostic, therapeutic and research purposes since the 1960s. Various bronchoscopic methods have been patented; several patents are presented here as examples. The concept of informed consent and assent applied to children and adolescents is also discussed. Conclusion: Significance of the procedural quality assurance in endoscopy is stressed, particularly, training methods not involving patients. It is also important to monitor endoscopic skills and objectively select capable trainees. © 2017 Bentham Science Publishers.