Why is yang disease easy to treat and yin disease difficult to treat?

In the era of Neijing, there is a saying that Yin Qi turned 40.

In Zhongjing era, the conduction along meridian was introduced from Yang meridian to Yin meridian. Yang diseases are mostly in the exterior, while Yin diseases are mostly in the interior. Therefore, Yin disease is the final stage of the disease.

According to syndrome differentiation of viscera, viscera diseases are easy to treat, but difficult to treat. Fu organs belong to yang, and viscera belongs to yin.

During the Jin and Yuan Dynasties, Danxi proposed that "Yang often has yin, and Yin often has deficiency".

From the nature of evil, wind, fire, summer heat and dryness belong to yang; Dampness and coldness belong to yin, and dampness and turbidity are difficult to dissolve.

Let's just say these points.