The effect of vitamins A, D3, E, and H supplementation on oxidative stress indices in Indian water buffaloes suffering from subclinical mastitis was investigated. Changes in the total oxidant capacity (TOC), total antioxidant capacity (TAC), nitric oxide (NO), and activities of glutathione peroxidase (GSH-Px), catalase (CAT), and superoxide dismutase (SOD) in milk were evaluated before and after the supplementation of vitamins A, D3, E, and H. The buffaloes suffering from subclinical mastitis revealed remarkable alterations in the milk oxidants/antioxidants balance shifted towards oxidative status. The buffaloes with subclinical mastitis revealed significantly (P ≤ 0.01) higher TOC, NO contents, and CAT activity, while TAC content and GSH-Px activity were significantly (P ≤ 0.01) lower in comparison with the healthy controls. However, SOD activity did not show any significant change. Supplementation of vitamins A, D3, E, and H to these animals revealed significant (P ≤ 0.01) reduction in TOC, NO, and CAT, while a significant (P ≤ 0.01) increase in TAC and GSH-Px activity was also evident. From the present study, it may be concluded that supplementation of these vitamins can help ameliorate the altered milk oxidants/antioxidants balance towards normalcy and, thus, ensue recovery from subclinical mastitis in the Indian water buffaloes.