Chronic alcohol use kills roughly 2.6 million people worldwide each year, and it does so through multiple pathways, not just one. Some are slow, unfolding over decades of damage to the liver, heart, and brain. Others are sudden: a fatal hemorrhage, a seizure during withdrawal, a car crash, or acute alcohol poisoning on a single night. Here’s how each of these pathways works.
Liver Failure and Cirrhosis
The liver processes nearly all the alcohol you drink, and years of heavy use gradually destroy it. Alcohol and its byproducts generate free radicals that damage liver cells, triggering waves of inflammation. Over time, the liver replaces functional tissue with scar tissue, a process called fibrosis. When scarring becomes extensive, it’s called cirrhosis, which develops in 10 to 20 percent of chronic heavy drinkers.
Cirrhosis is dangerous on its own, but the real threat comes when the liver can no longer compensate for the damage. This stage, called decompensation, produces several life-threatening complications at once. Fluid accumulates in the abdomen. Toxins that the liver normally filters, especially ammonia, build up in the blood and cause confusion, disorientation, and eventually coma. Scar tissue blocks blood flow through the liver, forcing blood to reroute through fragile veins in the esophagus and stomach. These swollen veins, called varices, can rupture without warning and cause massive internal bleeding. In one hospital study of patients admitted with decompensated alcoholic cirrhosis, roughly 27 percent died during that single hospitalization.
The bleeding itself is especially deadly because advanced liver disease also impairs the blood’s ability to clot. Combined with malnutrition and kidney failure, which often accompany late-stage cirrhosis, a variceal hemorrhage can become unsurvivable quickly.
Heart Damage
Years of heavy drinking physically enlarge and weaken the heart. Alcohol is toxic to heart muscle cells: it fragments their energy-producing structures, generates oxidative stress that damages proteins and DNA, and disrupts the calcium signaling that coordinates each heartbeat. Over time, the left ventricle stretches and thins. The heart compensates by activating stress hormones and retaining fluid, which temporarily maintains blood flow but ultimately accelerates the decline. The result is heart failure, where the heart can no longer pump enough blood to meet the body’s needs.
Heavy drinking also triggers dangerous heart rhythm problems. A single episode of binge drinking can cause atrial fibrillation, a rapid, irregular heartbeat sometimes called “holiday heart syndrome.” In rare cases, it can trigger ventricular fibrillation, a chaotic rhythm that causes cardiac arrest within minutes if untreated. Globally, an estimated 474,000 deaths from cardiovascular disease were attributed to alcohol in 2019 alone.
Cancer
Alcohol is a confirmed carcinogen. The U.S. Surgeon General has identified a causal link between alcohol use and at least seven types of cancer: breast, colorectal, esophageal, liver, mouth, throat, and voice box. These aren’t risks limited to the heaviest drinkers. Drinking roughly one drink per day increases the relative odds of mouth cancer by 40 percent compared to not drinking. At two drinks per day, that risk nearly doubles. For women, even one drink per day raises breast cancer risk by about 10 percent, and more than two daily drinks increases it by 32 percent.
In 2019, 4.4 percent of cancers diagnosed globally and 401,000 cancer deaths were attributed to alcohol. Among women, breast cancer accounts for about 60 percent of alcohol-related cancer deaths. Among men, liver and colorectal cancers together make up more than half.
Acute Alcohol Poisoning
Alcohol doesn’t only kill through years of accumulated damage. A single episode of extreme drinking can be fatal. Blood alcohol concentration (BAC) between 0.30 and 0.40 percent typically causes loss of consciousness and alcohol poisoning. Above 0.40 percent, the brain’s control over basic functions breaks down. The brainstem, which regulates breathing, can simply stop sending signals to the lungs. Death from respiratory arrest can occur while a person is unconscious, sometimes after vomiting and inhaling the vomit into the airway.
Pancreatitis
Alcohol is a direct toxin to the pancreas. Repeated heavy drinking can trigger acute pancreatitis, an intense inflammatory reaction that ranges from severe abdominal pain to multi-organ failure. The condition is classified as mild, moderate, or severe based on whether organs outside the pancreas begin to shut down. Severe cases, marked by persistent organ failure, drive most of the deaths. Alcohol-related pancreatitis carries a higher risk of pancreatic tissue death and organ failure compared to pancreatitis from other causes. Recurrent episodes can lead to chronic pancreatitis, which permanently destroys the organ’s ability to produce digestive enzymes and regulate blood sugar.
Brain Damage From Thiamine Deficiency
Chronic alcohol use depletes thiamine (vitamin B1), a nutrient the brain depends on to convert food into energy. Without enough thiamine, brain cells in specific regions begin to die, particularly in the thalamus and mammillary bodies, structures involved in memory and coordination. This condition, called Wernicke encephalopathy, causes confusion, vision problems, and difficulty walking. Brain imaging of affected patients reveals symmetrical lesions in the midbrain, hypothalamus, and cerebellum, along with shrinkage of key structures.
Less than 5 percent of people with Wernicke encephalopathy progress to a severely depressed level of consciousness leading to coma and death. But for those who survive without treatment, the damage often becomes permanent. Most progress to Korsakoff psychosis, a state of severe, irreversible memory loss. Very few individuals recover once they reach that point.
Withdrawal Seizures and Delirium Tremens
Paradoxically, stopping alcohol abruptly after long-term heavy use can also be fatal. Alcohol suppresses brain activity by enhancing calming signals and dampening excitatory ones. When alcohol is suddenly removed, the brain rebounds into a state of dangerous hyperexcitability. This can produce generalized tonic-clonic seizures, where the body alternates between rigid stiffening and violent convulsions. In the most severe form of withdrawal, called delirium tremens, the autonomic nervous system becomes extremely overactive. Heart rate, blood pressure, and body temperature spike uncontrollably, alongside hallucinations and profound confusion. Without medical intervention, delirium tremens can lead to cardiovascular collapse.
Accidents and Injuries
Alcohol impairs judgment, reaction time, and coordination, making fatal accidents far more likely. In the United States in 2022, 13,524 people died in motor vehicle crashes involving at least one alcohol-impaired driver, accounting for 32 percent of all traffic fatalities that year. Globally, the toll is much larger: 298,000 people died in alcohol-related road crashes in 2019, and more than half of those deaths (156,000) involved someone killed by another person’s drinking, not their own. Falls, drownings, fires, and other unintentional injuries add substantially to the total. In 2019, 700,000 deaths worldwide from injuries of all types were attributed to alcohol.
Suicide
Alcohol use disorder dramatically increases the risk of suicide. People with the disorder are roughly three times more likely to die by suicide than the general population, with studies showing an approximately 94 percent increased risk of completed suicide. When alcohol use disorder overlaps with other substance use disorders, the risk climbs even higher, to 10 to 14 times that of the general population. Alcohol lowers inhibitions, amplifies impulsivity, and worsens depression, making it both a long-term risk factor and an acute trigger. Many suicides occur during or shortly after heavy drinking episodes, even in people who might not have acted on suicidal thoughts while sober.
How These Risks Add Up
Most people who die from alcoholism don’t die from a single cause. The damage is cumulative and overlapping. A person with cirrhosis may also have a weakened heart. Someone with alcohol-related brain damage is more vulnerable to fatal falls. Cancer risk compounds alongside organ damage. Of the 2.6 million alcohol-attributable deaths recorded globally in 2019, 1.6 million were from chronic diseases like liver failure, heart disease, and cancer. The remaining million came from injuries, accidents, and infectious diseases made worse by alcohol’s suppression of the immune system. Men accounted for 2 million of those deaths, women for 600,000.