Abstract: Solutions (200 µL) of pharmaceutical formulations containing a phenothiazine were fed at 2.4 mL min-1 into an automated flow injection analysis system with 2.75 mM Fe(ClO4)3 - 10 M HClO4 solution as oxidizing agent and water as carrier solution. The products were passed to a spectrophotometer set at the λmax of the individual drug. Chlorpromazine, promethazine, promazine, methotrimeprazine, thioproperazine, fluphenazine, trifluoperazine and thioridazine were determined in the range 10 to 250 µg mL-1. The precision was better than 1% and a measurement rate of 120 h-1 could be attained. The method was evaluated by studying interference effects and recoveries and by the analysis of commercial formulations, the results of which were compared with those from the official USP method. The technique was used in content uniformity tests and for monitoring the dissolution of solid dosage forms in 0.1 M HCl.