Portal hypertension is prone to upper gastrointestinal bleeding: its clinical manifestations are mainly hematemesis or hematochezia; When the portal vein pressure increases, it causes varicose veins of gastric fundus and lower esophagus. Therefore, lower esophageal varices are an important manifestation of portal hypertension. Once the varicose esophagus and gastric fundus vein rupture, it often leads to acute bleeding, which is manifested as vomiting bright red blood. It is difficult to stop bleeding because of impaired liver function leading to coagulation dysfunction. The clinical manifestations are hematemesis, tarry stool and other symptoms of upper gastrointestinal bleeding.

Portal vein blood enters the inferior vena cava through the collateral circulation formed by superior rectal vein and rectal venous plexus, causing varicose rectal venous plexus. If it breaks, bloody stool may appear.

Similarly, if the portal vein passes through the umbilical vein and periumbilical vein network, then goes up into the superior vena cava through the thoracic and abdominal wall vein, and then goes down into the inferior vena cava through the inferior epigastric vein, it will cause superficial periumbilical varicose veins, which is what we call the "sea snake head" phenomenon.

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