Abstract: Evaluating the consistency of herb injectable formulations could improve their product quality and clinical safety, particularly concerning the composition and content levels of trace ingredients. Panax notoginseng Saponins Injection (PNSI), widely used in China for treating acute cardiovascular diseases, contains low-abundance (10%–25%) and trace saponins in addition to its five main constituents (notoginsenoside R₁, ginsenoside Rg₁, ginsenoside Re, ginsenoside Rb₁, and ginsenoside Rd). This study aimed to establish a robust analytical method and assess the variability in trace saponin levels within PNSI from different vendors and formulation types. To achieve this, a liquid chromatography-triple quadrupole mass spectrometry (LC-MS/MS) method employing multiple ions monitoring (MIM) was developed. A “post-column valve switching” strategy was implemented to eliminate highly abundant peaks (NR₁, Rg₁, and Re) at 26 min. A total of 51 saponins in PNSI were quantified or relatively quantified using 18 saponin standards, with digoxin as the internal standard. This study evaluated 119 batches of PNSI from seven vendors, revealing significant variability in trace saponin levels among different vendors and formulation types. These findings highlight the importance of consistent content in low-abundance and trace saponins to ensure product control and clinical safety. Standardization of these ingredients is crucial for maintaining the quality and effectiveness of PNSI in treating acute cardiovascular diseases.