A reliable and highly sensitive method is described for the determination of chloroxine in pharmaceutical preparations. It involves the formation of a complex between chloroxine and aluminum(III) in a micellar medium. The complex is a very fluorescent species, and there is a linear relationship between chloroxine concentration and fluorescence intensity over the range 2.0 x 10(-8)-5.1 x 10(-5) mol l-1. The limit of detection is 5 x 10(-9) mol l-1. The method can be easily adapted to a flow system using a three-channel manifold, the peak height being proportional to the chloroxine concentration over the range 5.6 x 10(-7)-5.6 x 10(-5) mol l-1. Manual and flow-injection procedures permit the determination of chloroxine in the presence of chlorquinaldol, and have been successfully applied to the determination of chloroxine in pharmaceutical preparations.