There is considerable interest in identifying dietary compounds which have the capacity to protect against chromosomal aberrations induced by antitumor agents. Fatty acids and their constituents are able to act as free radical scavengers. Doxorubicin (DXR) is an important chemotherapeutic agent, that also induces chromosome aberrations. Rat bone marrow cells treated simultaneously with olive oil (10 ml/kg body weight) and DXR (90 mg/kg body weight) developed significantly fewer chromosomal aberrations and abnormal metaphases than those treated with DXR alone.