CHLORPROMAZINE AND RENAL FUNCTION MEDICALIJOURNAL saluretic action. This effect could be explained by alterations of renal haemodynamics-that is, to be due to the rise of renal plasma flow and filtration rate, resulting in the changes of water and salt reabsorption. This possibility is not in the least excluded by the fact that the rise in glomerular filtration and renal plasma flow was much less than that in water and sodium excretion. Against this view, however, stands the fact that the changes in glomerular filtration and plasma flow were not always followed by similar changes in water and sodium excretion. It is to be noted in our experimenfs that out of 45 post-chlorpromazine clearance periods water excretion rose considerably in 11 cases, and sodium excretion in 7, in spite of a significant fall in glomerular filtration rate and renal plasma flow. In six normal persons chlorpromazine had no consistent effect on renal function. Diuresis increased in three cases, decreased in two, and in one was unaltered. Glomerular filtration decreased in three cases, and showed no change in the other three. The renal plasma flow diminished in three cases. was unchanged in one, and showed a slight but inconsiderable rise in the other two. Sodium excretion decreased in two cases, and did not alter in three.Our results will be communicated in detail in the Acta Medica Academiae Scientiarum Hungaricae.