can be recovered very easily thus minimising the loss of solvent in the recycling process toluene in a ratio of between 80 20 and 95 5 to the above mentioned alcohols has proved particularly suitable for this purpose particularly preferred is the above process wherein the plane bark is moistened with water before the extraction on the one hand this can improve the workability of the plane bark and on the other reduce the environmental dust pollution caused the process described above may be carried out continuously or as a batch process but the above process in which extraction is carried out continuously is preferred preferably the process is carried out continuously with a flow rate of the solvent mixture of 0 2 m 3 h to 6 m 3 h within a period of 2 h to 48 h preferably 5 h to 35 h particularly 15 h to 25 h battery extraction equipment of variable size and construction may be used the average daily amounts of powdered plane bark for extraction may be between 500 kg and 8 tonnes the above process wherein the extraction is carried out at a temperature of 20 to 110 u00b0 c preferably 40 to 90 u00b0 c particularly preferably 50 to 70 u00b0 c is particularly preferred for obtaining the betulinic acid from the crude extract the process is followed by some additional steps therefore the above process wherein.