The Four Tantras (Gyushi, rGyu-bzhi རྒྱུད་བཞི་) are the fundamental medical treatise, the rGyud-bZhi, is comprised of four sections, usually known as the Four Tantras:
- The Root Tantra
- The Explanatory Tantra
- The Oral Instruction Tantra
- The Last/Subsequent Tantra
（The Four Tantras； rGyu-bzhi； རྒྱུད་བཞི་)
The Four Tantras is believed to have been created in the twelfth century and still today is considered the basis of Tibetan medical practise. The Four Tantras is the common name for the text of the Secret Tantra Instruction on the Eight Branches, the Immortality Elixir essence. It considers a single medical doctrine from four perspectives. The basis of the Four Tantras is to keep the three bodily humors in balance: (rLung: wind; Tripe: bile; Beken: phlegm).
Root Tantra – A general outline of the principles of Tibetan Medicine, it discusses the humors in the body and their imbalances and their link to illness. This section is comprised of six chapters giving a brief outline of the whole text and comparing the medical system with a tree. Three roots sprout into nine stems, which branch out into 47 branches bearing 224 leaves. The nine stems represent the nine sections of medical science, the branches stand for general information and the leaves illustrate the details.
Three Roots:
- The root of Physiology and Pathology. The first root explains the human organism and its functioning and encompasses two stems, which stand for the healthy and the sick body. The healthy body is represented by three branches and 25 leaves, the sick body by nine branches and 63 leaves.
- The first stem, the healthy body, bears three branches. One of the branches represents the three humours, the other represents bodily constituents (nutritional essence, blood, muscle tissue, fat or fatty tissue, bones, marrow and regenerative fluid) and the third branch the three excretions of the body (faeces, urine and perspiration). Furthermore, the first stem bears two flowers standing for health and long life and three fruits representing religion, wealth and happiness.
- The second stem represents the sick body. This section deals with the three causes, the four conditions, the six different entrances, the locations and the fifteen pathways of the diseases. The association of advancement of diseases with the patient’s age, the seasons and the place where the patient resides is also discussed. Furthermore, the nine fatal disorders, the twelve contraindications due to inappropriate treatment and the condensation of all the disorders into hot and cold nature are also stated.
- The root of Diagnosis. The second root informs about the methods of diagnosis, the examination of the tongue and urine, the pulse diagnosis and the questioning of the patient regarding the symptoms of the disease, the way of living, etc.
- The root of Treatment. This root deals with therapeutic methods, diet, behaviour, medical preparations and external treatments.
Exegetical Tantra – The second Tantra encompasses 31 chapters and is concerned with the life cycle (conception, childbirth, functioning of the three humours and signs of death), causes, conditions and classification of the diseases. It specifies the properties of medicinal ingredients and explains in detail diet, behaviour and the rules for maintaining health, etc. It also contains a code which the physicians should up-hold in conducting his profession.
Instructional Tantra – The third Tantra consists of 92 chapters which mainly teach the 101 disorders of the three humours indicating their causes, conditions, symptoms and methods of therapy. The longest of the Tantras is mainly a practical application of treatment, it explains in detail illnesses and which humoral imbalance which causes the illness. This section also describes their specific treatments.
Subsequent Tantra – The last Tantra is comprised of 27 chapters, which deal with diagnosis (such as urine analysis and pulse reading), pacifying medicinal ingredients and their preparations (pills, powders, syrups, medicinal butters, etc.) evacuative medications (purgatives and emetics) and additional treatments (moxibustion, golden-needle therapy) which are applied when all other medicinal preparations have failed to cure the patient.
Sources:
Tibetan Medicine Today 