There is some evidence that probiotics improve eradication rates when added to a conventional treatment regimen. Lactobacillus-containing probiotics combined with quadruple therapy (such as bismuth, antacid medication, and two antibiotics) may be the most effective combination.[1][2][3] However, another meta-analysis found that probiotics may not increase the eradication rate, but may decrease adverse effects of triple or quadruple therapy.[4]
Synbiotics (which contain both probiotic microbes and their preferred prebiotic nutrient) may also improve eradication rates while reducing adverse treatment side effects.[5]
High-dose vitamin C supplementation and antioxidant-rich cranberry juice improved the efficacy of conventional treatment in a small number of studies, but more research is needed.[6]
Supplemental vitamin E, N-acetylcysteine, and curcumin have also been studied, but they don’t appear to improve eradication rates when added to conventional treatment.[7][6]