Provided are a liquid preparation wherein the pharmaceutically active ingredient is stabilized, and a stabilizing method therefor. A liquid preparation comprising a pharmaceutically active ingredient having a primary or secondary amino group (wherein the amino group does not constitute a part of the amide structure), an organic acid and a salt, which is substantially free of a reaction product of the pharmaceutically active ingredient and the organic acid.本案提供一種安定化藥學活性成分的液狀製劑，及其安定化方法。本案之液狀製劑包括含具有一級或二級胺基的藥學活性成分(其中的胺基不構成醯胺構造的一部分)，有機酸及鹽，該液狀製劑實質上不含該藥學活性成分與該有機酸的反應生成物。
