2-Methyl-3-amino-4,5-dihydroxymethylpyridine, 3-aminopyridoxol (I) is a potent antagonist of pyridoxol in the growth of S. carlsbergensis. Mn0_2 oxidation of (I) gave an aldehyde, 3-aminopyridoxal (II) of mp. 214〜215℃. UV, NMR, and mass spectral data of (II) were compared with those of pyridoxal. It was found that (II) existed mainly as the hemiacetal form (III) in aqueous solution and (II)/(III) was largest at pH 8.3-10.3. (II) was less reactive than pyridoxal with aromatic amine and gave Schiff's base only under heating. (II) inhibited the growth of S. carlsbergensis, though it was weaker than its parent compound (I). (Received May 25,1972)