Up to now the only effective therapy for recurrent abortion syndrome due to the absence of the so-called blocking-factor has been active immunotherapy with partner or third-party donor mononucleates. The Authors report their in vivo and in vitro experience with high-dose intravenous gammaglobulin (i IV Ig) in order to treat women with recurrent abortion syndrome. In the Authors opinion there are sufficient experimental reasons for continuing this research with IV Ig obtained from multiparous women plasma pools.