Vitamin C, a key nutrient with potent antioxidant and immunomodulatory properties, has been explored for its therapeutic potential in treating severe infections, particularly sepsis. This systematic review aims to evaluate the effectiveness of parenteral vitamin C in improving clinical outcomes in patients with severe infections. A comprehensive search of several databases, including PubMed, EMBASE, and the Cochrane Library, was conducted for studies published between January 2000 and June 2024. Included were randomized controlled trials, observational studies, and case reports that examined the use of parenteral vitamin C in adult patients with severe infections. Data extracted included study design, sample size, intervention specifics, and clinical outcomes. Quality was assessed using tools appropriate to each study design, such as the Cochrane Risk of Bias Tool and the Newcastle-Ottawa Scale. The review included nine studies with diverse methodologies. While individual studies reported benefits such as improved immune function and reduced oxidative stress, larger systematic reviews and meta-analyses did not demonstrate a significant reduction in mortality. The results indicate that while parenteral vitamin C may improve certain biochemical and physiological parameters, these improvements do not consistently translate into enhanced survival or substantial clinical benefits. Parenteral vitamin C shows potential in modulating immune response and reducing oxidative damage in severe infections. However, its impact on key clinical outcomes like mortality and long-term recovery remains uncertain. This review highlights the need for further high-quality, randomized controlled trials to clarify vitamin C's role in managing severe infections and define optimal therapeutic protocols.