Folic acid and derivatives in combination with other substances are classified in this group at separate 5th levels using the corresponding 50-series, if folic acid deficiency is the main indication. Folinates, used as antidotes, are classified in V03A. Combinations with iron, see B03AD and B03AE. Folic acid for diagnostic use is classified in V04CX - Other diagnostic agents.
Combinations with vitamin B12 are classified in B03BA.