There is some scientific evidence supporting the use of vitamin C (ascorbic acid) for the treatment of certain types of vaginitis, particularly bacterial vaginosis (BV). Several clinical studies, primarily conducted in Europe, have examined the use of vaginal vitamin C tablets as an adjunct or alternative to traditional antibiotic therapy. The rationale is that vitamin C, when administered intravaginally, can lower vaginal pH, thereby creating an acidic environment that may inhibit the growth of pathogenic bacteria while favoring the re-establishment of normal lactobacilli.

For example, a randomized, controlled trial published in European Journal of Obstetrics & Gynecology and Reproductive Biology (2006) found that vaginal vitamin C tablets led to significant improvement in BV symptoms and restoration of normal flora after six days of treatment. Other studies have shown similar results, with decreased rates of BV recurrence when vitamin C is used intermittently after conventional therapy. However, these trials often involve small sample sizes and variable methodologies.

Overall, while vitamin C is not a first-line, universally recommended treatment for vaginitis, the available evidence suggests a modest benefit, especially for recurrent or antibiotic-resistant cases of BV. The clinical use is primarily based on these scientific observations rather than longstanding traditional use. Further large-scale, high-quality studies are needed to establish definitive efficacy and safety.