Mechlorethamine hydrochloride is primarily used in the treatment of certain types of cancer, particularly Hodgkin's lymphoma and non-Hodgkin's lymphoma. It functions as a nitrogen mustard alkylating agent, which works by interfering with the DNA replication process in cancer cells, thereby inhibiting their growth and proliferation. This chemotherapeutic agent is often administered intravenously as part of combination therapy regimens to enhance its efficacy. Additionally, it is utilized in the palliative treatment of advanced stages of these cancers to alleviate symptoms and improve quality of life. In some cases, it is also employed in topical formulations for the management of cutaneous T-cell lymphoma, providing targeted treatment for skin lesions. Due to its potent nature, careful monitoring and management of potential side effects, such as bone marrow suppression and gastrointestinal disturbances, are essential during its use.