The performed studies can be regarded as the first ones in respect to the chemical characterization of black alder bark. Due to the relatively high content of tanning agents in black alder bark, it is recommended for obtaining tanning agents. For cellulose determination in black alder bark, the persulphate method developed by G.Zaķis and B.Neiberte is more suitable, in comparison with the classical Kirshner method. It has been found that, for extraction of tanning agents with hot water, the extraction time may be considerably decreased. Owing to the presence of polyphenols in black alder bark, its varied chemical modification is possible.