The determinations of gold levels in serum of patients with rheumatoid arthritis allow an exact monitoring of chrysotherapy. The atomic absorption spectrophotometry turned out to be superior for clinical use when compared with the neutron activation analysis. Under the conventional gold therapy serum levels increase with repetitive application achieving on maintenance therapy levels, which are in some cases under the recommended levels for effective therapy. The comparison of the clinical response of prolonged gold applications and serum levels revealed for instance that recurrent acute episodes of arthritis are more often with levels of 0.5 ppm or less, than with levels of 1.0 ppm or more. To what extent high dose therapy can increase the efficiency of chrysotherapy should still be determined, it should however be considered that with increased gold levels also more adverse reactions are to be expected. The predominant indication to determine serum gold level in the case of rheumatoid arthritis is the lack of any response to gold application. The serum gold level determination allows to differentiate between insufficient dosage and total ineffectivity of gold.