[Standardization of the birch leaf].

Dried leaves of Betula pendula Roth (14 batches) and B. pubescens Ehrh. (3 batches) present a similar flavonoid pattern. The mean levels of the principal flavonoid compounds were respectively: total flavonoids 3.29 and 2.77%, hyperoside 0.80 and 0.77%, avicularin (two forms) 0.57 and 0.26%, galactosyl-3 myricetol 0.37 and 0.18%, glucuronyl-3 quercetol 0.25 and 0.36%, quercitrin 0.14 and 0.12%. The flavonoid levels were higher in young leaves and lower in old leaves of B. pendula. 14 batches of commercial origin were also examined for a comparative study. Pharmacopoeial specifications are proposed for a revision of the monograph "Betulae folium".