The volume of birch plywood production in Latvia is illustrated by the 208 000 m3 of plywood sold in 2011 and about 562 000 m3 of processed birch veneer blocks. Wood residues such as bark, veneer shorts, cut off ends and others are used as a fuel. It would be more expedient to increase the birch wood utilisation degree by involving also birch outer bark in the processing cycle. It makes up 2% of the veneer blocks’ mass. At the J.S.C. “Latvijas Finieris”, about 6000 t per year of graded and milled outer birch bark could be produced for further processing. Birch outer bark consists of triterpenes, suberine, lignin and sugars, the content of which is ~35%, ~45%, ~9% and ~6%, respectively. The content of lupane type pentacyclic triterpenes in Latvian silver birch (Betula pendula Roth.) and downy birch (Betula pubescens Ehrh.) outer bark is among the highest ones for the species. The main components of the triterpene mixture are betulin, lupeol and betulinic acid (Figure 1), which are characterised by a poor solubility in organic solvents. Birch outer bark and its extracts have been used in folk medicine for ages. Nowadays, interest in triterpene derivatives, especially those of betulin, is increasing, since they are promising biologically active substances for treatment of cancer, HIV, obesity, the herpes virus and other diseases. In the most popular methods for triterpene extraction from outer birch bark, polar solvents such as ethanol and isopropanol or acetone are used. Unfortunately, these solvents, along with triterpenes, dissolve polyphenols, tannins, carbohydrates and other components of outer birch bark. The subsequent purification of extractives by recrystallisation is connected with the additional consumption of the solvent and losses of both the end product and the solvent. These operations are also labour-consuming.