Heavy metals generally refer to Hg, Cd, Pb, Cr, And metalloids with significant biotoxicity and heavy metal properties, such as As. and are sometimes referred to as general heavy metals such as Cu, Zn, Co, and Ni. Some of them are trace elements necessary for human health, but they also show virality if they accumulate in the body. Studies have shown that the accumulation of heavy metals in the body can cause diseases such as the nervous system, immune system, and cardiovascular system.

USP(United States Pharmacopeia) and JP(Japanese Pharmacopoeia) respectively specify that the total amount of heavy metals in gelatin is less than 50 ppm, wherein the As content should be less than 0.08 ppm (USP) and 1 ppm (JP), respectively, and the Hg content is less than 0.1 ppm. EP(European Pharmacopoeia) does not regulate the total amount of heavy metals, but the Fe, Zn and Cr contents are specified separately and must not exceed 30 ppm, 30 ppm and 10 ppm. It is worth mentioning that JP classifies gelatin, which limits the heavy metal limit of refined gelatin to 20 ppm. The total amount of heavy metals in the CP(Chinese Pharmacopoeia) 2000 edition hollow capsule product is consistent with USP and JP, but the As content is relaxed to 2 ppm. The CP 2010 edition of “Capsule Gelatin” has been reviewed to reduce the heavy metal content limit to 30 ppm and the As content to no more than 1 ppm. At the same time, the "gelatin empty capsule" consultation draft also changed the heavy metal limit to 40ppm.