A flow-injection method is described for the determination of furosemide in the range 1.0-50.0μmoll - 1 , with a detection limit of 0.22μmoll - 1 and a relative standard deviation of 2.1% at 10μmoll - 1 (n=10). The method is based on the chemiluminescence reaction of furosemide with cerium (IV) in sulphuric acid, sensitized by rhodamine 6G. By applying the method to tablets and injection solutions, it was found that the present method is relatively free from interference and tolerable to turbid solutions.