A bioactive triterpenoid betulonic acid is a valuable synthone for preparation of lupane- and oleanane-type derivatives with a wide spectrum of medical applications. A large-scale, cost-effective, and simple preparation of betulonic acid from birch (Betula pendula) bark is presented herein. The process includes four steps with the acid overall yield of 51% counting on betulin content in the extract and with the acid purity of 90% or more. The process can be employed for batch production of betulonic acid. (C) 2016 Elsevier B.V. All rights reserved.