According to Islamic teachings, arrogance is one of the main moral diseases, a plague for the health of the heart and an obstacle to achieving perfection and reaching heaven. Due to the importance and necessity of “moral health”, the present study, using its descriptive-analytical method and based on the verses and hadiths, seeks to find the root cause of arrogance disease in order to provide the basis for the root therapy. Research findings show: a) the root cause of the disease arrogance is “ignorance” and the arrogant have serious problems in three areas of self-knowledge, theology and cosmology; b) in the area of self-knowledge, the arrogant are unaware of their innate poverty and constant need for divine grace and are under the illusion of ownership; c) in the area of theology, the arrogant are unable to understand the ownership, sovereignty, power, and absolute richness of God Almighty; d) in the area of cosmology, they have not understood the reality of the world and the true nature of the world. Therefore, the main solution for the treatment of this deadly disease is to strive for self-knowledge, theology and cosmology