Abstract: The present invention relates to a pharmaceutical composition (a marrow cell proliferation accelerator, a radioprotective agent, a therapeutic agent for thrombocytopenia) comprising a compound represented by the following formula (A), and to a therapeutic or prophylactic method (a method for accelerating marrow cell proliferation, a method for protecting human against radiation damage, a method for the treatment of thrombocytopenia) characterized in that an effective amount of a compound represented by the following formula (A) is administered to human: ##STR1## wherein R represents ##STR2## (wherein R.sub.2 represents H or OH, X is an integer of 0-26) or --(CH.sub.2).sub.7 CH.dbd.CH(CH.sub.2).sub.7 CH.sub.3, and R.sub.1 is one of the substituents defined by the following (a) to (d):--CH.sub.2 (CH.sub.2).sub.Y CH.sub.3, (a)--CH(OH)(CH.sub.2).sub.Y CH.sub.3, (b)--CH(OH)(CH.sub.2).sub.Y CH(CH.sub.3).sub.2, (c)and--CH.dbd.CH(CH.sub.2).sub.Y CH.sub.3 (d)(wherein Y is an integer of 5-17).