Vitamin D or its analogues was found to induce autophagy in keratinocytes, macrophages, and various cancer cell types. Our preliminary findings indicated that 1α,25-dihydroxyvitamin D3 could induce cathelicidin expression and autophagy in cultured human gastric epithelial HFE-145 cells and reduced the intracellular survival of H. pylori in a co-culture system. It was also found that cathelicidin alone reduced the survival of drug-resistant strain of H. pylori. 1α,25-dihydroxyvitamin D3 also significantly reduced H. pylori colonization in mice, perhaps through the induction of cathelicidin in the stomach. These findings suggest that vitamin D not only could control H. pylori but also its drug-resistant strains in humans.