Rac-cis-Ambroxol-d5 is primarily used in research and development, particularly in the field of analytical chemistry. It serves as an internal standard in mass spectrometry for the accurate quantification of ambroxol in biological samples. This deuterated compound helps improve the precision and reliability of pharmacokinetic studies, enabling researchers to better understand the absorption, distribution, metabolism, and excretion of ambroxol in the body. Additionally, it is employed in the development and validation of analytical methods, ensuring consistency and accuracy in drug testing and quality control processes.