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-stasis 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 zang-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.

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-stasis 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 zang-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.