This study will be conducted as a phase I/II clinical trial. In addition to determining the maximum tolerated dose (MTD) of hydralazine, the phase I trial will be performed to identify unexpected toxicities that may occur when hydralazine is used in conjunction with neoadjuvant chemotherapy in normotensive patients with rectal cancer. Once the phase I trial is successfully completed, the phase II trial to evaluate the efficacy of hydralazine in producing a demethylation effect will begin.