Symptoms

Most of the alcohol ingested, after being absorbed by the digestive tract, is processed (metabolized) by the liver. As alcohol is processed, substances that can damage the liver are produced. Alcohol abuse can cause three types of liver damage:

fat accumulation (fatty liver or hepatic steatosis): the initial and most common consequence of excessive alcohol consumption. It is potentially reversible and occurs in over 90% of heavy drinkers
inflammation (alcoholic hepatitis): the liver becomes inflamed in about 10% to 35% of people who consume large amounts of alcohol in a short period
cirrhosis: about 10% to 20% of people develop cirrhosis (liver fibrosis or scarring with impaired function) when alcohol is consumed abusively over a long period

Alcohol concentration in beverages is often described in degrees, which are roughly twice the alcohol percentage. Different types of drinks contain different alcohol percentages:

beers: between 2% and 7%
wines: between 10% and 15%
distilled spirits: between 40% and 45%

Alcohol intake above 40g/day for men and 20g/day for women is considered potentially harmful.

Fatty liver usually does not cause symptoms.

Acute alcoholic hepatitis may present with general malaise, nausea, vomiting, jaundice (yellowing of the skin and mucous membranes), dark urine (choluria), and pale stools (acholia). This condition can become severe, requiring specific treatment, with increased risk of infections and even death.

As alcoholic liver disease progresses to cirrhosis, several other symptoms may appear, some quite characteristic, such as malnutrition, ascites (fluid accumulation in the abdomen), vomiting blood, anemia, gynecomastia (enlarged breast tissue), and episodes of mental confusion. Liver cancer occurs in 10% to 15% of people with established cirrhosis.