Abstract
The intramuscular injection of a small dose of vitamin B_<12> (2μg) on alternate days did not exert no significant effect on the urinary excretion of the vitamin, while the intravenous administration of 10〜200 μg of the vitamin caused the increase in the urinary excretion in accordance with the amounts of the administration. But the amount remaining in the body 6 hours after the injection reached the maximum of 20 μg in case of the administration of 50 μg and no more increase was observed even in cases of 100 and 200 μg. Vitamin B_<12> remaining in the body fell to 2.5〜8 μg 48 hours after the parenteral administration.
