Abstract: The accurate understanding and rational transmission of original dosages of classic formulas remain central to the inheritance and development of traditional Chinese medicine (TCM). During the transmission process, discrepancies in these original dosages have gradually emerged due to factors such as changes in systems of weights and measures, distortions associated with non-standard measurement units, errors, disarray, confusion, and omissions in textual transmission, and variations in medicinal material origins, processing methods, decoction techniques, and substitute applications. This paper systematically summarizes the primary causes of these transmission discrepancies and analyzes the pathways through which modern research validates these issues, covering aspects such as metrological verification, dose-effect-toxicity studies, clinical dosage comparisons, research on processing and dosage forms, and expert consensus. The issue of original dosages of classic formulas is not merely a matter of converting ancient measurements to modern equivalents. It should be based on the analysis of the medicinal material origins, combined with historical research, experimental evaluation, clinical evidence, and modern standards, to understand the scope of application of classic dosages under contemporary conditions in a layered manner. Future efforts should focus on gradually establishing a dynamic application system for dosages of classic formulas that balances historical evidence, modern validation, and clinical safety.