The present invention provides a composition for use in treating or preventing neoplasia, comprising an effective actein. The present invention also provides a composition for use in treating or preventing neoplasia, comprising an effective anti-neoplastic amount of an ethyl acetate extract of black cohosh. The present invention further provides a combination of anti-neoplastic agents, comprising an effective anti-neoplastic amount of an ethyl acetate extract of black cohosh and an effective anti-neoplastic amount of at least one additional chemopreventive or chemotherapeutic agent. Methods for treating and preventing neoplasia are also provided.