To the Leadership of the Bone Marrow Bank, USA,

In reference to your request, I discussed the following with our esteemed Rebbe (Rabbi Yosef Shalom Elyashiv Shlit”a). His response is as follows:

The bone marrow of donors has in many instances saved the lives of many of our brethren. Because the bank is under government guidelines, they are forbidden to share any information in regard to the bone marrow recipient. As a result, many potential donors inquire whether they are obligated to participate (by offering their bone marrow). Our Rebbe Shlita responded that since it was determined by experts that there is no physical danger to the donors (except in very isolated instances), it is a mitzvah for these donors to donate their marrow (with exception to those specific instances).

May the merit of saving one Jewish life, stand in their stead for eternal blessing. 

Rabbi Joseph I. Efrati

Head of the Institute for Advanced Studies in Halacha for Agricultural Settlements