The effect of TRH analogue, YM14673: N alpha-[[(S)-4-oxo-2-azetidinyl]-carbonyl)-L-histidyl-L-prolinamide] dihydrate, on traumatic brain edema were studied in male Wistar rats. The cerebral contusion was produced by Feeney's dropping weight method. Animals were randomly divided into 4 groups: normal group and YM14673 (0.1 mg.kg-1, i.p.), YM14673 (1.0 mg.kg-1, i.p.) and a control group (given equal volume of physiological saline, i.p.) after cerebral contusion. Contents of water in brain tissue were measured. These results suggest that treatments with YM14673 significantly reduced brain edema than control group (P < 0.05).