Gastric ultrasound can be performed with water in place of some of the contrast agent. For most patients, water can be used to replace some of the contrast material. Water as a contrast agent can also make the stomach and intestines stretch, reduce gastrointestinal peristalsis, after injecting water to do CT examination, you can also observe the whole colon or small intestines; if injected into the stomach, you can observe the average thickness of the gastric wall, so gastric color ultrasound can use water to replace part of the contrast agent. If water is used as the contrast agent, it can also observe the specific lesion area, judge the development of the lesion area, and understand whether the local metastasis or proliferation has occurred, so gastric ultrasound with water instead of contrast agent is also possible. If you need to do gastric ultrasound, it is recommended to consult a doctor in time and analyze whether water can be used instead of contrast agent under the guidance of a professional physician, and once any abnormality is found, it should be treated in time.