Type 2 Diabetes Mellitus (T2DM) is a chronic, multifactorial metabolic disorder characterized by insulin resistance, β-cell dysfunction, and systemic metabolic imbalance. In Ayurveda, this condition correlates with Prameha, particularly Madhumeha, caused by derangement of Kapha, Meda, and Kleda along with impaired Agni. Modern management of T2DM focuses on glycaemic control, yet often neglects the underlying metabolic, oxidative, and inflammatory mechanisms. Mustadikwathghana Vati, an Ayurvedic polyherbal formulation containing Cyperus rotundus (Musta) and other Kaphahara-Medohara herbs, is described in classical texts as effective in Prameha. This single-case clinical study aimed to evaluate its therapeutic efficacy as an adjuvant in T2DM. A 52-year-old male with classical diabetic symptoms (Prabhuta Mutrata, Pipasa, Daurbalya) was treated with Mustadikwathghana Vati (500 mg twice daily before meals) for 90 days along with a regulated diet and lifestyle regimen. Outcomes were assessed through clinical and biochemical parameters—FBS, PPBS, HbA1c, BMI, and lipid profile—recorded at baseline and monthly intervals. Marked improvement was observed: FBS declined from 210 to 124 mg/dL, PPBS from 320 to 172 mg/dL, and HbA1c from 8.9 to 6.8%. Lipid profile and BMI also improved, accompanied by ~75% symptomatic relief without adverse effects. Pharmacological actions such as Deepana-Pachana, Medohara, and Kleda-Shoshana contributed to the therapeutic outcome. The results suggest Mustadikwathghana Vati acts through both traditional and molecular mechanisms—enhancing insulin sensitivity, modulating oxidative stress, and restoring Agni. This case reinforces the potential of integrative Ayurvedic therapy as a safe, holistic adjunct in T2DM management.