Drug regulation is crucial for public health, ensuring that medicines are safe, effective, and high quality. Without proper regulation, substandard and falsified medicines can lead to ineffective treatments, drug resistance, and fatalities. The World Health Organization (WHO) outlines essential functions of medicine regulation, including licensing, quality assessment, surveillance, and adverse reaction monitoring. Postmarketing surveillance (PMS) plays a vital role in monitoring the quality, safety, and efficacy of medicines after they enter the market. This study examines WHO guidelines for conducting PMS to enhance medicine quality. A semisystematic document analysis approach was employed, using Google Scholar to identify relevant documents from reputable sources such as the WHO. The primary document analyzed was the WHO’s “Guidelines on the Conduct of Surveys of the Quality of Medicines.” Data management was performed via Microsoft Excel, and Adobe Acrobat was used for document annotation. Manual coding facilitated the extraction of pertinent information, and text analysis was conducted via Voyant Tools. The WHO guidelines cover objectives, survey management, methodology, sample collection, testing, data management, and publication. The key themes identified include quality assurance, survey methodology, laboratory testing, data collection, regulatory compliance, risk management, and the importance of accurate survey results. Corpus analysis revealed the document’s focus on medicine quality, sampling techniques, and regulatory oversight. Thematic and collocational analyses highlighted recurring patterns and associations, such as the emphasis on “quality medicines” and the prevalence of terms related to compliance and safety. The WHO guidelines provide a comprehensive framework for conducting PMS, emphasizing rigorous quality control measures, systematic surveys, and stakeholder involvement. Ensuring the quality of medicines through standardized procedures is crucial for public health. The document underscores the role of national medicine regulatory authorities (NMRAs) in maintaining medicine standards and highlights the need for continuous surveillance to identify and address substandard medicines. This study reinforces the importance of PMS in safeguarding public health by ensuring the availability of safe and effective medicines.