[PROBLEMS] To develop a clinically useful composition and endoscopic observation method using the properties of WOS. [Solution] A composition containing fat as a constituent component, which is oral, tube, or transendoscopy A composition for improving diagnostic ability, wherein the fat is absorbed into a gastric tumor by being administered and loaded in an effort to facilitate the discovery and qualitative diagnosis of the tumor by an endoscope. Moreover, the fat is absorbed in the gastric tumor of the subject by administering or loading the diagnostic ability improving composition to the subject orally, tube, or endoscopically, and the tumor is detected by endoscope An endoscopic observation method characterized by facilitating qualitative diagnosis. Thus, by applying and loading the diagnostic ability improving composition of the present invention before endoscopic observation, the gastric tumor is whitened, and the gastric tumor can be detected and qualitatively diagnosed by endoscopic observation more easily. It became possible to do. [Selection] Figure 5【課題】WOSの性質を利用した，臨床上有用な組成物および内視鏡観察法の開発【解決手段】脂肪を構成成分として含む組成物であって，経口的または経管，経内視鏡的に投与・負荷することにより，前記脂肪を胃腫瘍に吸収させ，内視鏡による腫瘍の発見や質的診断を容易にすることを特徴とする診断能改善組成物。また，前記診断能改善組成物を，経口的または経管，経内視鏡的に被験者に投与・負荷することにより，前記脂肪を前記被験者の胃腫瘍に吸収させ，内視鏡による腫瘍の発見や質的診断を容易にすることを特徴とする内視鏡観察方法。これにより，本発明の診断能改善組成物を内視鏡観察前に投与・負荷することにより，胃腫瘍が白色化され，内視鏡観察による胃腫瘍の発見および質的診断を，より容易にすることが可能となった。【選択図】図５
