The medicine service may investigate and diagnose many lower respiratory tract disorders, including inflammatory airway disease, recurrent airway obstruction, pleuropneumonia and thoracic neoplasia. Many mature and geriatric pleasure horses have mild coughing at exercise that is infrequently investigated, and considered normal by the owner. At Newnham Court Equine Clinic, we encourage owners to investigate these cases, to improve athletic capability and quality of life of these mature horses, to enable them to keep active for longer. Diseases of the lungs are investigated by detailed clinical examination, thoracic auscultation and percussion, digital radiography and ultrasonographic examination of the thoracic cavity. Videoendoscopy allows visualisation of the trachea and major bronchi, and collection of samples of fluid for cytological and bacteriological examination in our on-site laboratory. In horses presenting with pleural effusion, samples of fluid may be taken from the thoracic cavity and lung biopsy performed where appropriate, to allow definitive diagnosis. Management of these cases, including selection of appropriate inhaled medication can be advised upon. Repeat evaluations, to assess response to treatment, is encouraged.