The disclosure relates to the use of one or more oral dosage forms comprising (i) N-[8-(2-hydroxybenzoyl)amino]caprylic acid or a pharmaceutically acceptable salt thereof, (ii) vitamin B12, and optionally (iii) folic acid, in the manufacture of a medicament for rapidly normalizing vitamin B12 levels in a patient having a vitamin B12 deficiency and an average vitamin B12 level below about 350 pg/mL. The medicament is for daily administration for a period of at least 15 days, wherein the medicament provides a daily total amount of N-[8-(2-hydroxybenzoyl) amino]caprylic acid or a pharmaceutically acceptable salt thereof of from about 50 to about 250 mg and a daily total amount of vitamin B12 of from about 0.5 to about 2 mg, and wherein the vitamin B12 level in the patient is normalized within 15 days. The disclosure also relates to the use of the dosage form for treating a patient with elevated methyl malonic acid (MMA) or homocysteine levels.
