MRI of the brain is virtually harmless to the human body. MRI is an imaging of cell nuclei through magnetic field, unlike X-rays, there is no radioactivity and it is harmless to human body, so it is a relatively safe examination program. MRI of the brain can be used to examine glioblastoma, glioma, cerebral arteriovenous malformation, etc. However, some people are not suitable for this examination. 1. pregnant women: pregnant women should avoid MRI of the brain, which may affect the pregnant woman and the fetus and cause miscarriage. 2. people with contrast allergy: some patients need to do intensive MRI, which requires contrast injection, and people who are allergic to contrast should avoid this examination. 3. If the body is equipped with a pacemaker, metal stent, denture and other metal objects, the results may be inaccurate, or the metal may become hot, or the metal may be displaced, causing structural damage to the body. Some patients may experience some side effects after MRI, such as dizziness, regurgitation, nausea, vomiting, etc. They can rest properly and drink more water, which will usually heal on their own. If the symptoms are serious, you can apply medication to regulate intestinal flora under the guidance of your doctor.