For a study, researchers sought to objectively review and consolidate the information on the effects of vitamin C-based regimens for patients with sepsis or septic shock. In May 2021, a comprehensive search was conducted to find randomized clinical trials (RCTs) that tested vitamin C-based regimens as adjuvant therapy for patients suffering from sepsis or septic shock. Investigators used the Cochrane Risk of Bias table to evaluate the RCTs’ methodological quality, and they applied the GRADE technique to evaluate the evidence for its level of certainty. They included 20 RCTs (2,124 participants). Evidence from medium to very low certainty demonstrated that vitamin C compared to placebo may lower all-cause mortality up to 28 days (relative risk [RR] 0.60, 95% CI 0.45 to 0.80, 4 RCTs, 335 participants). Considering the other comparisons (vitamin C alone or combined with thiamine and hydrocortisone, compared to placebo, standard care, or hydrocortisone), there was almost no difference or very unsure proof for adverse outcomes, SOFA score, ICU length of stay, acute kidney injury, mechanical ventilation- and vasoactive drugs-free days up to 28 days. To provide improved aid in decision-making, additional RCTs of higher methodological quality had an increasing number of participants, and clinically relevant outcomes were required.