OUTLINE: Patients complete a questionnaire containing a smoking and dietary log to assess cigarette and cruciferous vegetable consumption. Patients receive phenethyl isothiocyanate orally 4 times a day for 30 days. Cohorts of 3-6 patients receive escalating doses of phenethyl isothiocyanate until the maximum tolerated dose (MTD) is determined. The MTD is defined as the dose preceding that at which 2 of 6 patients experience dose limiting toxicities. Patients are followed on days 35, 36, and 43.