The present invention relates to compounds or pharmaceutically acceptable salts thereof for use in the treatment of cough, in particular idiopathic chronic cough, cough variant asthma, cough associated with thoracic tumour or lung cancer, viral and post-viral cough, upper airways cough syndrome (UACS) or post nasal drip cough, and cough associated with disorders such as gastro oesophageal reflux disease (both acid and non acid reflux), chronic bronchitis, chronic obstructive pulmonary disease (COPD), interstitial lung disease (the as idiopathic pulmonary fibrosis (IPF)), congestive heart disease, sarcoidosis and infection (the as whooping cough).