This paper summarizes Professor CUI Yinglin's clinical experience in treating pediatric mitochondrial encephalomyopathy based on the original

qi

theory. It is proposed that original

qi

depletion is the core pathogenesis， and the fundamental therapeutic principle is consolidating the root and replenishing original

qi

. Clinically， the disease is classified into four syndrome types， including insufficiency of kidney essence， spleen

qi

depletion， liver-kidney

yin

deficiency， and original

qi

constraint and stagnation accompanied by phlegm-sta

sis obstructing the collaterals. Correspondingly， self-formulated

Gujing Yiyuan Decoction

（固精益元汤） can be used to tonify the kidney and replenish essence， reinforce and strengthen original

qi

. Modified

Yiyuan Decoction

（益元汤） is used to fortify the spleen and supplement

qi

， consolidate the root and replenish original

qi

. Modified

Da Bu Yuan Decoction

（大补元煎） is employed to nourish the liver and kidney， and replenish original

qi

. Self-formulated

Huatan Quyu Formula

（化痰祛瘀方） is used to supplement

qi

and activating blood， resolve phlegm and unblocking the collaterals. Medication is flexibly adjusted according to syndrome differentiation， with simultaneous attention to the functional balance of the z

ang

-

fu

（脏腑） organs and the harmony of

qi

， blood，

yin

， and

yang

， which may provide useful guidance for the clinical treatment of pediatric mitochondrial encephalomyopathy.