Six bottles of chemotherapeutic agents for injection, as marketed in the United States c. 1993. Clockwise from center: bleomycin, an antitumor antibiotic; vincristine, a spindle poison; dacarbazine, an alkylating agent; cyclophosphamide, a nitrogen mustard; doxorubicin, an anthracycline; and etoposide, a topoisomerase inhibitor.