Acute overdosage with daunorubicin will result in severe myelosuppression (mainly leukopenia and thrombocytopenia), gastrointestinal toxic effects (mainly mucositis) and acute cardiac complications. Very high single doses of daunorubicin may be expected to cause acute myocardial degeneration (within 24 hours) and severe myelosuppression (within 10–14 days). Treatment should aim to support the patient during this period. Delayed cardiac failures have been observed with anthracyclines up to 6 months after an overdose. Patients have to be observed carefully: if signs of cardiac failure arise, they should be treated along conventional lines.