Objective: To study the content difference of the principal component (As2S2) and the soluble arsenic salt (As2O3) in realgar and it processed products from different origins. Method: As2S2 content was determined by titration based on the analysis method of realgar recorded in Chinese Pharmacopoeia (2010 edition)

and As2O3 content was detected using AFS-230E Atomic fluorescence spectrophotometer. Result: The contents of As2S2 and As2O3 were significantly different in realgar and its processed products from different origins. After processing

As2S2 content in the processed products was obviously increased

while As2O3 content was significantly reduced. Except that As2S2 content in realgar and its processed products from Jilin province and Jiangsu province was less than 90.0%

the rest of the samples can meet the pharmacopoeia requirements

and As2O3 content in all of the processed products can be controlled below 1.7 mg· g-1. Conclusion: This findings can provide a reference for guiding rational clinical applications of realgar.