This product is an organic iron compound, which can precipitate when the pH value is less than 4 and become soluble when the pH value is higher (pH7.5-8). In addition, the preparation is not digested by pepsin, but hydrolyzed by trypsin at neutral pH value. The iron contained in this product is protected by protein membrane, which will not cause gastric mucosal damage, and will be released in the duodenum, and generally will not cause gastrointestinal tolerance problems.