We tried Cofrel<sup>？？</sup> (Pyrexyl<sup>？？</sup> 1-(2-benzyl phenoxy)-2-piperidino-propane phosphate) which is non-narcotic, to evaluate its clinical effect on cough due to respiratory tract diseases-35 cases. 1) Thirty two cases among 35 cases disclosed remarkable effectiveness (91.4% of efficacy) 2) It was almost equally effective in dry cough, productive cough and barking cough. 3) Speed of response was very rapid in 21 cases(60.0) moderately rapid in 12 cases(34.3%). 4) Palatability were excellent in all cases and side effect was not observed. It is very difficult to evaluate effectiveness of anti-tussive drug. However, we concluded that Cofrel is a quite effective medicament for cough in respiratory diseases in children.