In the course of developing new drugs to treat cancer, researchers have developed less toxic formulations of currently used active compounds. At the 18th San Antonio Breast Cancer Symposium [San Antonio, Texas, US; December 1995], the results of phase I and II trials of liposome-encapsulated formulations of doxorubicin and daunorubicin were presented. Currently, the new formulations appear to be better tolerated, but less effective, than standard preparations.