The use of injectable gold in the treatment of rheumatoid arthritis (RA) is hampered by the high incidence of adverse reactions of which myelotoxicity is potentially the most serious. Regular full blood count (FB C) monitoring prior to each injection, a practice which requires much time and effort, has never been fully evaluated. Of 154 patients who were started on gold and followed by the life-table method for up to 10 years, five patients were withdrawn from treatment because of myelotoxicity, thrombocytopenia in all cases: the two most serious cases occurred early at 3 and 7 months after starting treatment; three mild cases occurred at 17, 37 and 60 months, were of slow onset and reversed spontaneously. Clearly, FBC monitoring is justifiable in the first two years of treatment when the incidence of adverse reaction is highest. Further investigation is required to justify this practice after two years of uncomplicated treatment.