Whether a carotid plaque of 11mm is dangerous or not cannot be generalized, and the nature of the plaque needs to be assessed comprehensively. Carotid plaque is a manifestation of carotid atherosclerosis, which occurs at the bifurcation of the common carotid artery. Lipid deposition at the bifurcation of the common carotid artery leads to intima-media thickening and plaque formation. After the formation of carotid plaque, it is more dangerous if the blood vessel is narrowed or occluded, or if the carotid plaque is dislodged. Gradual increase of carotid plaque can cause stenosis or occlusion of blood vessels, resulting in insufficient blood supply to the brain, leading to dizziness, confusion, and transient blackout, which is more dangerous. Due to the instability of plaque, carotid plaque can be dislodged, small plaque dislodgment can induce stroke, and serious carotid plaque dislodgment can even cause large-scale cerebral infarction, which is also more dangerous. Therefore, for patients who have formed carotid plaques, it is recommended that they should cooperate with doctors for treatment in time, so as to avoid serious conditions and even life-threatening.