This deep-dive podcast episode explores the critical world of drug impurities and their impact on pharmaceutical safety. The discussion covers the ICH guidelines (Q3A through Q3E) that govern impurity control, sophisticated analytical techniques for detection, and real-world applications in both traditional pharmaceuticals and emerging substances like cannabis and psilocybin. The episode breaks down complex concepts like purge factors, nitrosamine impurities, and hyphenated analytical techniques, while emphasizing the importance of quality control in ensuring safe, effective medications.