The antineoplastic activity of erucylphosphocholine (ErPC) on C6 rat glioma cells and the human glioblastoma cell lines A172 and T98G was studied in vitro. ErPC exerted concentration- and time-dependent cytostatic and cytotoxic actions. The effects of ErPC on C6 cells were stronger than hexadecylphosphocholine and similar to 1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine. The human cell lines were more sensitive to ErPC (LC50 = 36 microM and 29 microM) than C6 cells (LC50 = 70 microM) (48 hours, WST-1-test). Morphological characteristics of apoptotic cell death were observed. Rats bearing intracerebral and subcutaneous gliomas were treated with intravenous ErPC for 30 days to determine the antitumor effects of ErPC in vivo. ErPC accumulation in subcutaneous tumors was higher than in brain tissue. Peripheral tumors revealed a better response than CNS-tumors. There was a strong negative relationship between the concentration of ErPC and the weight of peripheral tumors. ErPC is considered to be promising for chemotherapy of malignant brain tumors.