The Thomsonian Manual Volume 2, authored by Samuel Thomson and published in 1836, is a foundational text in the field of botanical medicine. This volume continues Thomson’s advocacy for a natural, plant-based approach to healing, emphasizing the body’s innate ability to recover when supported by appropriate herbal remedies. Thomson’s system was developed as an alternative to the conventional medical practices of his time, which often involved invasive procedures and the use of toxic substances. Instead, he proposed a method that focused on restoring the body’s natural heat and vitality through the use of specific herbs and treatments.​

Central to Thomson’s methodology is the classification of remedies into six categories, each serving a distinct purpose in the healing process. Class No. 1 includes emetics like lobelia, used to cleanse the stomach and promote perspiration. Class No. 2 comprises stimulants such as capsicum, aimed at raising and maintaining the body’s vital heat. Class No. 3 consists of astringents like bayberry, intended to cleanse the stomach and bowels and remove canker. Class No. 4 features bitters, including hydrastis and populus, to restore digestion and correct morbid secretions. Class No. 5 encompasses restorative tonics like wild cherry, designed to strengthen the stomach and bowels. Finally, Class No. 6 includes antiseptics such as myrrh, used to tone the stomach and prevent mortification.​

Thomson’s treatment protocol, often referred to as a “course,” involves a systematic application of these remedies. The process begins with administering a hot bayberry tea to prepare the body, followed by an enema composed of bayberry and lobelia to cleanse the bowels. A steam bath is then applied to induce perspiration, and additional doses of bayberry tea and capsicum are given to sustain the body’s heat. After the patient has been thoroughly cleansed and has perspired adequately, they are placed in a warm bed to rest. Subsequent treatments may include digestive bitters to restore appetite and strengthen the digestive system.​

Thomson’s approach to medicine was deeply rooted in the belief that disease resulted from a loss of the body’s natural heat and obstructions within the system. By employing his six classes of remedies in a structured manner, he aimed to eliminate these obstructions, restore vital heat, and support the body’s self-healing capabilities. His emphasis on using readily available herbs and simple treatments made his system accessible to many, particularly in rural areas where conventional medical care was scarce. The Thomsonian Manual Volume 2 thus represents a significant contribution to the tradition of herbal medicine, reflecting a holistic and naturalistic approach to health that continues to influence alternative medicine practices today.