NEW MATERIAL:A compound expressed by formula I and pharmaceutically allowable salt of the compound (R1 is H, 1-5C alkyl, aryl or aralkyl; R2 and R3 are H, 1-5C alkyl, guanyl, substitutable aryl or aralkyl with a proviso that R2 and R3 are not simultaneously H).

EXAMPLE: A t-4-guanylmethylcyclohexane carbohydroxamic acid.hydrochloride.

USE: Used as an anti-ulcer agent having both of protease-inhibiting activity and urease-inhibiting activity.

PREPARATION: Aminomethylcyclohexane carboxylic acid expressed by formula II or a reactive derivative of the acid is reacted with a compound expressed by formula III, or is reacted with hydroxylamine and further reacted with a compound expressed by formula IV to afford the compound expressed by formula I. Each reaction temperature is preferably from -10°C to 40°C.