Patients with cirrhosis may develop abdominal fluid in the later stages of the disease due to hepatic decompensation and portal hypertension, which can lead to an enlarged abdomen. The specific reasons are as follows. 1. Portal hypertension: in the late stage of liver cirrhosis, the increased pressure of portal vein will lead to the increased blood pressure of gastrointestinal capillaries and the leakage of tissue fluid into the abdominal cavity to form ascites. 2. Decrease in effective blood volume: Decrease in effective circulating blood volume and decrease in renal blood volume will activate the renin-angiotensin system. This leads to a decrease in sodium excretion and urine output, producing ascites. 3. Decrease in plasma colloid osmotic pressure: Due to hepatic hypoperfusion, patients will experience a decrease in serum protein, a decrease in plasma colloid osmotic pressure, and fluid will leak out of the capillaries, producing ascites. 4. Decreased inactivation of aldosterone and antidiuretic hormone: Due to hepatic hypoplasia, the hepatic inactivation of aldosterone and antidiuretic hormone is reduced, resulting in sodium retention and increased ascites. 5. Elevated hepatic sinusoidal pressure: elevated hepatic sinusoidal pressure leads to increased hepatic lymphatic fluid production, and the lymphatic fluid will leak into the abdominal cavity and produce ascites. If the above symptoms occur, it is recommended to go to the hospital in time for early and regular treatment.