<p>The negative impacts and toxicity of conventional medications prompt the exploration of complementary therapies. The plethora of bioactive compounds and phytoconstituents inherent in herbs, endowed with profound therapeutic properties, not only underscores their centuries-old utility in traditional medicine but also catalyzes their burgeoning integration into complementary and alternative medicines, thereby fueling the rapid expansion of the herbal medicine industry and its increasingly pivotal role in the global healthcare economy. Herbs are used in pharmaceutics in two primary manners: either their chemicals are isolated and utilized to formulate drugs, or they are administered alongside drugs to create herb–drug interactions. Both processes possess distinct mechanisms; herb–drug discovery includes extraction, purification, fractionation, screening, structural elucidation, and pre-clinical research, while herb–drug interaction mechanisms involve pharmacokinetics or pharmacodynamics. A critical examination of these two approaches reveals varying degrees of mechanisms, efficacy, safety, and cost-effectiveness. Notably, there is a paucity of comparative analysis between these mechanisms, leaving a knowledge gap regarding which approach optimizes treatment benefit while minimizing risks. This review aims to compare the therapeutic efficacy, safety profile, and potential benefits of incorporating herbs into modern medicines versus their concurrent use alongside conventional medications, highlighting the pros and cons of both approaches. Collectively, this review suggests that compared to adjunctive herbal therapy, the incorporation of phytochemical extracts into pharmaceutical formulations offers a more precise and controlled delivery of bioactive compounds, thereby optimizing therapeutic efficacy and reducing variability in patient response.</p> Graphical Abstract <p></p>