OBJECTIVES: I. Determine the efficacy of arsenic trioxide in terms of rate of response (complete or partial remission), duration of response, relapse free survival, and overall survival in patients with relapsed or refractory Hodgkin's disease. II. Evaluate the toxicities of this agent in this patient population. III. Elucidate the mechanism of action of this treatment by measuring induction of apoptosis and caspace activation when given to these patients.