Vitamin C (ascorbic acid) is a water-soluble vitamin that is believed to have beneficial effects in patients with serious and critical illnesses. It is an antioxidant and free radical scavenger that has anti-inflammatory properties, affects cellular immunity and vascular integrity and serves as a cofactor in the production of endogenous catecholamines. ^1.2Because people may need more vitamin C in situations of oxidative stress, vitamin C supplementation has been evaluated in many diseases, including severe infections and sepsis. Because SARS-CoV-2 infection can cause sepsis and acute respiratory distress syndrome (ARDS), the potential role of high doses of vitamin C in improving inflammation and vascular injury in patients with COVID-19 is being studied.