A Medical Formulary Based on the United States and British Pharmacopoeias by Laurence Johnson, first published in 1881, is a comprehensive compilation of medicinal formulas and preparations. This work integrates official standards from both the United States and British pharmacopoeias, along with numerous French, German, and unofficial preparations. Spanning over 400 pages, the formulary serves as a practical reference for physicians, pharmacists, and medical students, reflecting the medical practices of the late 19th century.​

The book meticulously details the preparation and administration of various medicinal compounds, emphasizing the importance of standardized measurements and procedures. It includes a wide array of formulas, ranging from common remedies to more specialized treatments, providing insights into the therapeutic approaches of the time. By consolidating information from multiple national pharmacopoeias, Johnson aimed to create a unified resource that would be accessible and useful to medical professionals across different regions.​

In addition to official preparations, the formulary incorporates numerous unofficial and traditional remedies, reflecting the diverse medical practices and cultural influences of the era. This inclusion highlights the transitional period in medicine, where empirical knowledge and traditional practices were gradually being integrated into a more standardized scientific framework. The book also addresses the properties and uses of various medicines, providing guidance on their therapeutic applications.​

A Medical Formulary stands as a testament to the evolving field of pharmacology in the 19th century, bridging the gap between traditional remedies and emerging scientific approaches. Its comprehensive nature and attention to detail make it a valuable historical document, offering insights into the medical knowledge and practices of its time. For contemporary readers and historians, the formulary provides a window into the development of modern pharmacological standards and the integration of diverse medical traditions.