In recent years, new agents active in solid malignancies have been developed. Gemcitabine is one such agent. It is a deoxycytidine analogue structurally related to cytosine arabinoside. Gemcitabine is activated by deoxycytidine kinase in three steps of phosphorylation into difluorodeoxycytidine triphosphate, which when incorporated into DNA, leads to chain termination. Gemcitabine has been shown to have activity in pancreatic, breast, non-small cell lung carcinomas as well as in carcinomas of unknown primary site. Because of its mild toxicity profile, gemcitabine has been used in combination with other chemotherapy agents. There is evidence of in vitro and in vivo synergy between gemcitabine and the platinum compounds.