Some writers have argued that vitamin B12 injections are unnecessary, citing a study that claimed oral vitamin B12 (2,000 mcg/day) produces higher serum vitamin B12 levels than intramuscular injections.2_ However, in that study, the serum concentrations were measured one month after the last intramuscular injection was given, whereas the oral doses were being taken daily during that time. Interestingly, although this study was published in a specialty journal (Blood), it contained the following disclaimer: “The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked ‘advertisement’ in accordance with 18 U.S.C. section 1734 solely to indicate this fact.” Although the study did confirm that oral vitamin B12 is effective for the treatment of vitamin B12 deficiency (including pernicious anemia), it did not compare oral and intramuscular administration with respect to their short-term (1-7 days) effects on serum levels. Consequently, this study cannot be used to justify the claim that oral vitamin B12 produces the same pharmacological effect as does intramuscular vitamin B12.