The Turkic people in Central Asia started to convert to Islam in the mid-8th century. Islam, just like other religions in other cultures, had an impact on various aspects of Turkish life, including literacy, language, and culture. It seems that the concept of four humors has been adopted by Turkic people along with the conversion to Islam. The humoral pathology theory based on the idea that human bodies contain basic four humors, or fluids (i.e., blood, yellow bile, black bile, and phlegm), was the mainstream medical system for hundreds of years. After a paradigm shift in medicine in the mid-19th century, this theory was replaced with the modern germ theory. However, the reflections of the four humors theory can be observed in the Kutadgu Bilig, an 11th century Central Asian Turkic 'mirror for princes,' which contains pieces of advice on ideals of statecraft. It is also possible to find the traces of medical understanding of Turkic people from that period in this work. The evaluation of the manuscript shows that it contains valuable information related to humoral pathology theory. Some of the examples are that it emphasizes that the harmony of the humors is essential for a healthy life; the relationship between temperament and age, season, food, and four qualities (hot–cold and wet–dry) is expressed. In conclusion, the Kutadgu Bilig is a good sample of work containing information on the humoral pathology theory in Central Asian Turkish medicine from the 11th century.