Rosacea is a kind of chronic skin damage that occurs in the middle of the face and centers on the external nose. The cause of the disease is still unclear, and it may be related to genetic factors and environmental factors, etc. 1. Genetic factors: patients with rosacea have obvious family agglomeration, especially the onset of female patients is closely related to the genetic factors; 2. Abnormalities in vascular function: emotional excitement or tension can cause redness on the face, especially on the nose, and the reflexes of vasodilatation nerves are strong in some of the patients, and slight stimulation can cause persistent redness on the face. Vasodilatation nerve reflex is strong, slight stimulation and can cause persistent facial redness, easy to occur rosacea; 3, facial stimulation: sunlight, hot and cold or hot diet and other stimulating factors can affect the vasodilatation nerves, so that the facial skin changes, triggering and exacerbating rosacea; 4, digestive disorders: such as gastric acid reduction, dyspepsia, constipation and other digestive disorders may be the causative factors; 5, endocrine disorders: Rosacea often appears in amenorrheic women, or often aggravated during menstruation, sometimes accompanied by ovarian disease, and endocrine dysfunction; 6, impaired skin barrier function: studies have shown that the water content of the stratum corneum of the lesions of patients with rosacea decreases, and most of the patients’ sebum content decreases, and the loss of transdermal water increases, resulting in skin barrier dysfunction; 7, other: excessive reproduction of follicular helminth mites, bacillus vegetableis proliferation, gastrointestinal Helicobacter pylori caused by infection, may be the triggering factors for rosacea.