Obesity is one of the most prevalent health concerns over the past few decades.Besides diabetes and cardiovascular disease,obesity is also connected to multiple types of cancers[1,2].However,the mechanism underlying obesity-related cancers is unclear.Previous research found that obesity alters the microbiota grown in the gastrointestinal tract[3],where the microbes produce inflammatory metabolites[4].And obesity-induced inflammation is involved in liver cancer[5].Recently,Yoshimoto et al uncovered the missing link,by which obesity promotes the production of proinflammatory and carcinogenic bile acids via shaping gut microbiota,and leads to hepatic inflammation and hepatocellular carcinoma (HCC)[6] (Figure 1).