Pretreatment for 4 days with 10 mg/kg coenzyme Q10 (CoQ) or 1 day with 85U alpha-tocopherol (Vit E) produced equal reduction in the acute toxicity of 0.5 mg/kg anthramycin (ANTH). Twenty-seven days after ANTH, 40 percent of control mice survived, those pretreated with CoQ or Vit E displayed 73 and 80 percent survival. A 17.5 mg/kg dose of adriamycin (ADR) produced a percent survival-time curve resembling that produced by 0.5 mg/kg ANTH. At this dose of ADR, however, the protection afforded by CoQ and Vit E was minimal and not statistically significant (p less than 0.05). CoQ or Vit E may be of value at reducing the toxicity of anticancer agents other than the anthracyclines.