Dactinomycin, also known as dactinomycin, is an antibiotic and chemotherapeutic agent derived from the bacterium Streptomyces parvinus. It intercalates DNA, inhibiting RNA synthesis, which disrupts cellular function and leads to cell death, making it effective against various types of cancer, including Wilms' tumor, rhabdomyosarcoma, and testicular cancer. Dactinomycin is typically administered intravenously and is used in combination with other treatments to enhance its efficacy. Its use can be associated with significant side effects, including myelosuppression and mucositis.