Guided by the

yin

fire theory， this paper explores the etiology， pathogenesis， and principles of syndrome differentiation and treatment for pediatric food accumulation transforming into heat syndrome. It is proposed that deficiency in the root and heat in the manifestation constitute the core pathogenesis of this condition in children. The dynamic evolution of the disease can be summarized into four stages， weakness of the spleen and stomach with impaired transportation and transformation， abnormal ascending and descending of the spleen and stomach with stagnation of

qi

dynamics， internal generation of

yin

fire that ascends to the domain of earth， and reckless movement of ministerial fire with floating deficiency heat. According to the pathogenetic characteristics at different stages， corresponding treatments are adopted， including a self-formulated

Bupi Pill

（补脾丸） to strengthen the spleen， tonify

qi

， and restore transportation and transformation，

Buzhong Yiqi Decoction

（补中益气汤） to regulate ascending and descending and harmonize the

qi

dynamics of the middle

jiao

（焦），

Bupiwei Xieyinhuo Shengyang Decoction

（补脾胃泻阴火升阳汤） to drain fire with sweet and warm methods and guide heat downward， and

Shengyang Sanhuo Decoction

（升阳散火汤） to guide fire back to its origin， restrain

yin

and secure the exterior.