The invention provides an application of indole-3-methanol, diindolylmethane and derivatives thereof in preparing medicament for treating cardiac failure caused by anthracycline, which can prevent a body from free radical damage caused by doxorubicin and other anthracyclines so as to inhibit and stop attack of cardiac failure caused by anthracyclines. The indole-3-methanol, diindolylmethane and derivative compounds thereof have good curative effect in animal models with cardiac failure induced by anthracyclines, meanwhile, the small molecular medicament used in the application has easily acquired active components, has low cost and stable property, is convenient for storage and transportation, and has wide application prospect.