Workers maintain a machine in a factory producing Tibetan medicine in Xining, western China, photo fromCRIENGLISH.com/Dominic Swire.

Tibetan medicine is practiced in many countries including India, Nepal, Bhutan and Mongolia, as well, of course, as China. The concept of Tibetan medicine is based on the Buddhist belief that all illnesses are ultimately derived from the three poisons of the body, namely ignorance, attachment and aversion. Most of the cures recommended by Tibetan medicine are herbal in origin.

Our day started with a visit to the Tibetan Medicine Culture Museum in Xining, capital city of western China's Qinghai province. The centre offers a comprehensive history of this fascinating system of health with hundreds of cultural relics on display. Like most great museums, the collection is so expansive, it's impossible to take everything in during one visit. But the section that most impressed me was the display of tangka. These are graphical representations of the practice of Tibetan medicine, containing all kinds of information such as the symptoms of various diseases, what cures to take in which circumstances and even advice on how a doctor ought to act. The ancient pictures have been produced in the form of colourful posters-each approximately the size of an A1 piece of paper. They range from large depictions of the human body and its various ailments to cartoon-like storyboards. The history of the tangka is shrouded in mystery-no one knows exactly when or how this tradition of recording information began, but the art has been traced back at least as early as the 7th century AD. The detailed pictures are fascinating to look at alone, but to fully understand them, one needs to refer to the ancient literature, which is housed in the museum's library. Opening a book with English translation here can show you, for example, that the picture of a patient, a doctor and a man riding a horse means that a doctor must be wholly absorbed in the treatment of a patient, as if controlling a horse. The old books are all oblong in shape and wrapped in a decorated golden material, which gives the shelves of the library a feel of a bank vault rather than a place of study.