In order to investigate the feasibility of transmucosal delivery of the model peptide, LHRH, metabolism of LHRH and inhibition effect of medium chain fatty acid salts were studied in rabbit mucosal homogenate. LHRH incubated in homogenates of rectal(RE), nasal(NA) and vaginal(VA) mucosa were assayed by HPLC. Five to six degradation products of LHRH were deterted and the degradation of LHRH$(500;{mu}g/ml)$ followed the first order kinetics. The main degradation products were found as $LHRH^{1-5}(M-I)$, $LHRH^{1-3}(M-II)$ and $LHRH^{1-6}(M-III)$ by the method of amino acid analysis. The half-lives of LHRH in the mucosal homogenates were found to be less than 20 min at protein concentration of 2.5 mg/ml with the order of VA>NA>RE mucosal homogenate. Medium chain fatty acid salts such as sodium caprylate $(C_8)$, sodium caprate $(C_{10})$ and sodium laurate $(C_{12})$ at the concentration of $0.5%{sim}1.0%$ inhibit the proteolysis of LHRH significantly. The addition of sodium laurate(0.5%) into the NA and VA mucosal homogenates protected LHRH completely from the degradation.