The present invention provides a composition which contains hydrogen gas or dissolved hydrogen as an active ingredient and which is for suppressing or preventing an abnormality of the intestinal environment in a subject, wherein the abnormality is selected from the group consisting of bacterial translocation and abnormal composition of bacterial species in the intestinal microbiota.本申請提供一種組合物,其係包含氫氣或溶氫作為有效成分之用於抑制或預防受驗體之腸內環境之異常者,該異常係選自由細菌移位及腸內菌叢之菌種組成異常所組成之群之中。