To investigate the interventional effects of Buyang Huanwu Decoction（补阳还五汤）combined with Huanglian Jiedu Decoction（黄连解毒汤）（modified）on cognitive impairment in diabetic encephalopathy and explore its potential mechanisms through magnetic resonance spectroscopy（MRS）and metabolic indicators.

A prospective，randomized，controlled，double-blind study was conducted，enrolling119 patients with type 2 diabetes mellitus（T2DM）-associated cognitive impairment and Qi-Yin deficiency with phlegm-stasis syndrome from the Traditional Medicine Center of Jinhua Central Hospital between January 2024 and December 2024.The participants were randomized into an experimental group and a control group.The experimental group received Buyang Huanwu Decoction combined with Huanglian Jiedu Decoction（modified）combined with standard hypoglycemic therapy，while the control group received mecobalamin，piracetam and standard hypoglycemic therapy.The intervention lasted 12 weeks.Montreal Cognitive Assessment（MoCA）scores，hippocampal N-acetylaspartate/creatinine（NAA/Cr），frontal choline/creatinine（Cho/Cr）via MRSand serum metabolic indicators［glycosylated hemoglobin（HbA1c），homocysteine（Hcy），malondialdehyde（MDA）］were assessed at baseline，week 6 and week 12.Traditional Chinese Medicine（TCM）syndrome scores and adverse reactions were concurrently evaluated.

The experimental group showed a 15%～20% greater improvement in MoCA total scores compared to the control group，with significantly elevated hippocampal NAA/Cr（≥0.3）and reduced levels of Hcy and MDA（P<0.05）.Buyang Huanwu Deoction and Huanglian Jiedu Decoction（modified）demonstrated neuroprotective effects by improving neuronal metabolic status，regulating methionine pathways and mitigating oxidative stress.Regarding TCM syndrome scores，both primary and secondary symptom scores in the treatment group showed significant reductions，with an overall syndrome remission rate of 92.3%，which was significantly higher than that of the control group（P<0.001）.The degree of improvement was strongly correlated with the increase in MMSE scores（r＝-0.82，P<0.001）.No serious adverse events were observed in either group during the treatment period，and the treatment group demonstrated good safety.

Buyang Huanwu Decoction combined with Huanglian Jiedu Decoction（modified）exhibits favorable safety and cognitive improvement，potentially alleviating diabetic encephalopathy progression through modulation of neuro-metabolic homeostasis and systemic oxidative pathways，providing theoretical and mechanistic support for integrated TCM-Western medicine interventions.