IT IS AN ALKYLATING AGENT PRODUCING HIGHLY REACTIVE CARBONIUM ION INTERMEDIATES WHICH TRANSFER ALKYL GROUPS TO CELLULAR MACROMOLECULES BY FORMING COVALENT BONDS. IT IS CYTOTOXIC AND RADIOMIMETIC (LIKE IONIZING REDIATION) AND IS CELL CYCLE NON-SPECIFIC, I.E. ACT ON DIVIDING AS WELL AS RESTING CELLS. IT IS THE FIRST NITROGEN MUSTARD ; HIGHLY REACTIVE AND LOCAL VESICANT, CAN BE GIVEN ONLY BY I.V. ROUTE.