IL10 and polyposis: Using mice singly infected with H. typhlonius or H. mastomyrinus, we showed that VitC treatment also reduced polyposis (Fig. 2c, d) and levels of 8-oxoG in IL10−/− mice (Supplementary Fig. 3c–e) without major effects on inflammation or Helicobacter colonization (Fig. 2a, Supplementary Fig. 2).