An official drug is one that is contained in the Pharmacopoeia. In prescribing an official drug it is not necessary to write U. S. P., as that is understood.

In prescribing a preparation of the National Formulary, if it is particularly desirable to get the N. F. product, it is usually best to specify N. F., as pharmacists are not always very familiar with the formulae of this valuable guide.

While it is inadvisable for a prescriber to even try to confine himself to the Pharmacopoeia and National Formulary, they certainly contain the vast majority of drugs that should be used. These books should be in the library of every physician, and he should so familiarize himself with their contents as to know what agents he can get so well standardized and give them the preference.