To bridge the linguistic and conceptual divide between Eastern and Western approaches to health, Dr. Loh-Jie developed a foundational diagnostic framework called the Eight Principles. These principles act as a set of binary filters, that get to the heart of health conditions and guide their treatment protocols. This method is integrated with Western diagnostics, utilizing their insights where they prove beneficial. They are a set of four pairs: hot/cold, interior/exterior, yin/yang, and excess (full)/deficient (empty).

Hot/Cold

This principle describes the temperature nature of a condition. For example, if you have a high fever and are sweating, it’s considered a hot condition. If you’re shivering and feel chilled to the bone despite blankets, it’s a cold condition and treatment protocols will take this into account.

Interior/Exterior

This refers to the depth of the disease within the body. Many common colds, for instance, start on the exterior (like catching a virus through your nose). The body tries to fight it off at this superficial level. If the cold lingers for weeks, settling deep in your chest and making you feel very weak, it has moved to the interior. Some diseases, like organ problems, may start in the interior and are generally seen as more serious. TCM practitioners use different methods and herbal formulas depending on whether a condition is interior or exterior.

Excess (Full)/Deficient (Empty)

These terms describe both the strength of the disease and the body’s response to it.

  • An excess or full condition means there’s something aggressive or strong present, like a chest cold with a tight, heavy feeling in the lungs, full of inflammation and phlegm. The illness feels acute and powerful.
  • A deficient or empty condition describes a weakness in the body, often after a prolonged illness. For example, six months after a severe chest cold, the lungs might be weak and damaged, leading to shortness of breath with little effort, a weak cough, and overall low vitality. The original pathogen might be gone, but the body’s ability to defend itself or perform its usual functions (like breathing or digestion) is compromised.

Yin/Yang

While complex and deserving of a deeper discussion, Yin and Yang are fundamental concepts in TCM that underpin all these principles. They represent opposing yet interconnected forces that exist in everything, including the body and disease states. Understanding their interplay is key to a complete diagnosis.

Combining the Principles

TCM practitioners combine these principles for a more refined diagnosis and treatment plan. You could have an exterior, full, hot condition in the lungs (like an acute flu with fever and yellow phlegm), or an exterior, full, cold condition (like a cold with clear mucus and chills). Symptoms guide the practitioner in determining if a condition is “hot” (e.g., yellow phlegm, fever, sore throat) or “cold” (e.g., clear mucus, chills, pale skin).

Real-world patients often present a mix of symptoms, and the TCM practitioner’s skill lies in discerning the “root” cause from the “branch” symptoms, and deciding which to treat first. This is just a basic look at some of the differential diagnostic methods used in TCM, and many advanced techniques exist beyond this overview.