The history of the department of biochemistry can date back to 1890 when the Siriraj medical school, the first medical school in Thailand, was founded. At the beginning, the teaching of biochemistry was a part of the basic physiology course taught by Dr. George B. McFarland.

For several decades thereafter, the Siamese government, through the tireless efforts of HRH Prince Mahidol, the father of modern medicine and public health of Thailand, felt a strong need to modernize Siriraj hospital as well as the medical school and its medical curriculum. Thus, the Rockefeller Foundation was called for to help revise and improve the medical teaching in 1923. The foundation had sent Professor E.C.Albritton to the medical school to help improve the teaching in physiology. As soon as he was appointed as the head of the department of physiology, he started revising the content of the physiology course, which was made to include three important medical areas, i.e., physiology, pharmacology, and biochemistry. He also set up the physiology laboratory to include the laboratory course in the medical curriculum.

All three subjects were taught under the same course in the department of physiology until 1965 when the department of pharmacology and the department of biochemistry spun off to become independent departments. Professor Dr. Sanong Unakul served as the first head of the department of biochemistry, which has since become an integral and important part of the medical school in teaching of biochemistry, both to medical and graduate students, and conducting biomedical research.