In order to prevent abuse or excessive usage of sulphur fumigation in the primary processing of Chinese crude drugs and ensure the quality, safety and effectiveness of traditional Chinese medicines, the State Food and Drug Administration (SFDA) formulated the limit standard for residual sulphur dioxide in Chinese crude drugs and prepared slices of Chinese crude drugs. The draft standard is open to public opinion by the Chinese Pharmacopoeia Commission as of June 10, 2011.

According to the draft standard: the maximum residue limit of sulfur dioxide is 400 mg/kg for 11 specified kinds of Chinese crude drugs and prepared slices of Chinese crude drugs which are traditionally use sulphur fumigation, such as Chinese yams, achyranthes root and lobed kudzuvine root; the maximum residue limit of sulfur dioxide is 150 mg/kg for all the other kinds of Chinese crude drugs and prepared slices of Chinese crude drugs.

The deadline for the comments solicitation will be September 9, 2011. The standard will be formally promulgated and come into effect after finalized according to the public opinions.