Cycloartenol (I), 24-methylene-cycloartanol (II), 4 [alpha]-methylstigmasta-7,24(28)-dien-3[beta]-ol ("[alpha]-sitosterol") (III) and the acetate of methyl betulinate (V) have been isolated from birch wood. The composition of the wood extractives is given. The mass spectrum of 4 [alpha]-methylstigmasta-7,24(28)-dien-3[beta]-ol is discussed.