Mechlorethamine is a chemotherapy medication primarily used to treat certain types of cancer, including Hodgkin's lymphoma and non-Hodgkin's lymphoma. It belongs to a class of drugs known as alkylating agents, which work by damaging the DNA of cancer cells, preventing them from dividing and growing. This drug is typically administered through an injection, either into a vein or as part of a combination therapy. While effective, mechlorethamine can cause side effects such as nausea, vomiting, and a decrease in blood cell counts, which may increase the risk of infections and bleeding.