There are very many causes of superficial thrombophlebitis, including the following: 1. Inflammatory stimulation. For example, in common mastitis patients, a thrombophlebitis can be seen below the breast, which is caused by local inflammatory stimulation; 2. Drug stimulation. Commonly used drugs, such as quinolone anti-inflammatory drugs or chemotherapeutic drugs, if only purely from the peripheral veins, often drug stimulation of endothelial cells caused by acute inflammation can be manifested; 3, physical stimulation. For example, many patients need to do chemotherapy nowadays, and they will put a central venous catheter through peripheral vein, called PICC. PICC catheter in superficial vein can cause localized thrombosed superficial phlebitis; 4, superficial varicose veins. Chronic varicose veins can lead to localized blood stasis and the formation of thrombosed superficial phlebitis; 5. Inflammatory vasculopathy. Localized manifestations in the superficial veins, such as thrombotic occlusive vasculitis are typically characterized by wandering superficial phlebitis; 6. Smoking and cold can lead to thrombosed superficial phlebitis.