Cosmegen 'Lyovac', also known as Dactinomycin, is a chemotherapy medication used in the treatment of various types of cancer, including Wilms' tumor, rhabdomyosarcoma, Ewing's sarcoma, and certain types of ovarian cancer, among others. It belongs to a class of drugs known as antineoplastic antibiotics, which work by binding to DNA and inhibiting RNA synthesis, thereby preventing the replication of cancer cells and slowing or stopping their growth. Cosmegen 'Lyovac' is administered under the supervision of a healthcare professional, typically through intravenous injection. Due to its potent effects, it is essential to monitor patients closely for side effects during treatment. This medication plays a crucial role in comprehensive cancer care, often being used in combination with other treatments to enhance therapeutic outcomes.