PURPOSE: To provide a new hydroxylamine compound having strong specific inhibiting activity on the enzyme ornithine decarboxylase, that is, anti-growth property.

CONSTITUTION: A compound of formula I [R1 is amino or formula II (R3 is an alkyl, hydroxyalkyl, alkoxyalkyl, phenyl, etc.; R4 is H, an alkyl, etc., or R3 and R4 form an alkylene or benzoalkylene together); R2 is an alkyl], or a salt thereof, e.g. N-(3-aminoxy-2-fluoropropyl)-methylamino dihydrochloric acid salt. The compound of the formula I is prepared by reacting, e.g. a compound of formula III (Y is a group which is optionally substituted into F or is optionally substituted by F), with a fluorinating agent.