Penicillamine causes lots of problems. It is also a highly effective treatment which is capable of achieving long-term control of rheumatoid arthritis (RA). The physician's approach to the management of side effects is therefore determined by the patient's response as well as by adverse reactions. The severity of the adverse reaction and its natural history will influence the decision about treatment. There are just 3 options in a patient who develops a side effect due to penicillamine. Treatment may be stopped. It may be stopped and reintroduced, usually using a lower dose and cautious increases. Or it may be continued. Skillful management of side effects is an essential part of the treatment of RA with penicillamine. A therapeutic opportunity has been lost when treatment is stopped in a patient whose disease is controlled. The potential for side effects also influences the decision to use penicillamine and the surveillance required for patients receiving it.