Melphalan is a chemotherapy drug that is used to treat various types of cancer, such as multiple myeloma, ovarian cancer, and breast cancer, among others. It works by damaging the DNA in cancer cells, which prevents them from multiplying. Synonyms for melphalan include L-phenylalanine mustard, L-PAM, and phenylalanine mustard. These alternative names are used because melphalan is derived from the amino acid phenylalanine. Other similar drugs that may be used in conjunction with melphalan for cancer treatment include azacitidine, busulfan, and carmustine. These drugs all work to treat cancer by damaging or killing cancer cells, but they may have different side effects and interactions with other medications.