HP and gastric cancer: A blinded randomized placebo-controlled trial conducted in Linqu County, Shandong Province, China, compared the anti-gastric cancer effects of three interventions, including anti-HP treatment with amoxicillin and omeprazole for 2 weeks and garlic (extract and oil) and vitamin (C, E, and selenium) supplementation for 7.3 years (1995–2003) (including 3,365 residents of a high-risk region for gastric cancer in total) (Li WQ.