Three anacardic acids (1-3) have been isolated as cytotoxic agents against BT-20 breast carcinoma cells from the cashew Anacardium occidentale (Anacardiaceae) apple juice. In addition to these anacardic acids, the cytotoxicity of their 13 congeners (4-16) isolated from the cashew nut and nut shell oil has also been examined. Anacardic acids (1-4), cardols (5-8), and methylcardols (9-12) have been found to exhibit moderate cytotoxic activity against both BT-20 breast and HeLa epithelioid cervix carcinoma cells.