Dangers of Alcohol: What Drinking Does to Your Body and Brain

The dangers of alcohol go beyond hangovers. Regular drinking affects the brain, liver, heart, and increases cancer risk in ways that add up over time.

What You'll Discover:

• Immediate dangers that occur when you drink.

• How alcohol changes brain function and chemistry.

• Long-term damage to the liver, heart, and other organs.

• The connection between alcohol and cancer risk.

• Who faces the greatest health risks from drinking.

• Whether alcohol-related damage can be reversed.

• Options for reducing or eliminating your risk.

Alcohol contributes to more than 178,000 deaths in the United States each year, making it the third-leading preventable cause of death after tobacco and obesity. According to the Centers for Disease Control and Prevention, alcohol plays a causal role in more than 200 diseases, injuries, and other health conditions.

The first thing to know about the dangers of alcohol is that they affect nearly every system in your body. Some effects are immediate. Others develop gradually over years of drinking. Understanding both helps you make informed decisions about alcohol.

Immediate Dangers of Alcohol

Every time you drink, alcohol impairs your judgment, coordination, and reaction time. These effects begin within minutes and last until the alcohol is processed out of your system.

Accidents and injuries are the most common immediate danger. Alcohol plays a role in about 30% of all motor vehicle deaths. Beyond driving, drinking increases the risk of falls, drownings, burns, and other unintentional injuries. A good example of this is something as simple as cooking dinner after a few drinks, where impaired coordination increases the chance of cuts or burns.

Alcohol poisoning occurs when blood alcohol levels become high enough to affect basic body functions. Symptoms include confusion, vomiting, seizures, slow breathing, and unconsciousness. So, how much alcohol causes poisoning? The answer varies by person, but consuming more than 4-5 drinks in under two hours puts most people at risk.

Dangerous interactions happen when alcohol is mixed with other substances. Combining alcohol with opioids, sedatives, or certain prescription medications can suppress breathing and heart function. Even common over-the-counter medications like antihistamines can have amplified effects.

Risky behavior increases under the influence because alcohol affects the frontal lobes of the brain. This reduces inhibitions and impairs decision-making, which can lead to situations you would normally avoid.

How Alcohol Affects the Brain

Alcohol reaches your brain within about 5 minutes of drinking. From there, it changes how your brain functions in several ways.

Short-term effects include the relaxation and lowered inhibitions that people associate with drinking. Alcohol enhances the effects of GABA, an inhibitory neurotransmitter that slows brain activity. At the same time, it suppresses glutamate, further slowing brain function. This is why speech becomes slurred and coordination suffers as blood alcohol rises.

Alcohol also triggers dopamine release in the reward center of the brain. This creates pleasurable feelings and reinforces the desire to drink again. Over time, the brain adapts to this artificial dopamine surge, which is part of what makes alcohol habit-forming.

Memory problems are common even with moderate drinking. Alcohol interferes with the hippocampus, the brain region responsible for forming new memories. This causes "blackouts," which are gaps in memory where you cannot recall events that happened while drinking. Something to consider is that blackouts can occur at moderate blood alcohol levels, not just during extreme intoxication.

Long-term brain changes develop with chronic heavy drinking. Research from the University of Oxford found that people who drank 4 or more drinks daily had nearly 6 times the risk of hippocampal shrinkage compared to non-drinkers. Even moderate drinkers showed more shrinkage than abstainers.

For more on how alcohol specifically affects the brain, see our article on effects of alcohol on the brain.

Dangers to Major Organs

Alcohol causes damage throughout the body. The liver, heart, and pancreas are particularly vulnerable.

Liver damage is the most well-known danger of chronic drinking. The liver processes about 90% of the alcohol you consume. This workload causes progressive damage over time:

• Fatty liver disease - Fat accumulates in liver cells. Usually reversible within weeks of stopping drinking.

• Alcoholic hepatitis - Inflammation that causes liver damage. Can improve significantly if drinking stops.

• Cirrhosis - Scar tissue replaces healthy liver tissue. Permanent, but stopping drinking prevents further progression.

Heart and cardiovascular damage results from chronic alcohol use. According to the National Institute on Alcohol Abuse and Alcoholism, heavy drinking can cause high blood pressure, cardiomyopathy (weakening of the heart muscle), arrhythmias, and increased stroke risk.

Pancreatic damage is another serious concern. Alcohol can cause pancreatitis, a painful inflammation that requires hospitalization in severe cases. Chronic pancreatitis increases the risk of pancreatic cancer and diabetes.

Digestive system effects include gastritis (inflammation of the stomach lining), acid reflux, and impaired nutrient absorption. Chronic drinking can lead to malnutrition even in people who eat adequate diets because alcohol interferes with vitamin and mineral absorption.

Alcohol and Cancer Risk

The World Health Organization classifies alcohol as a Group 1 carcinogen, the same category as tobacco and asbestos. This means there is sufficient evidence that alcohol causes cancer in humans.

Alcohol consumption increases the risk of several types of cancer:

• Head and neck cancers - Mouth, throat, and voice box cancers are 2-3 times more common in regular drinkers.

• Esophageal cancer - Risk increases substantially, especially when combined with smoking.

• Liver cancer - A leading cause, usually developing from cirrhosis.

• Breast cancer - Each drink per day increases risk by about 7-10%. Even moderate drinking carries elevated risk.

• Colorectal cancer - Heavy drinking is associated with increased colon and rectal cancer risk.

So, why does alcohol cause cancer? The answer involves several mechanisms. When alcohol is processed by the body, it converts to acetaldehyde, a compound that damages DNA and prevents cells from repairing that damage. Alcohol also impairs the absorption of nutrients that may protect against cancer.

Research indicates alcohol causes approximately 100,000 cancer cases and 20,000 cancer deaths in the United States annually. The risk increases with the amount consumed. There is no level of alcohol consumption that carries zero cancer risk.

Mental Health Dangers

Many people drink to relax or manage stress. However, chronic alcohol use typically makes mental health worse over time.

Anxiety and depression are closely linked to alcohol use. While alcohol can temporarily reduce anxiety, the rebound effect as it wears off often increases anxiety levels. Chronic drinking disrupts the brain chemistry that regulates mood, contributing to both anxiety and depressive disorders.

If it seems like a cycle that feeds itself, that's because it often is. People drink to feel better, but drinking makes the underlying problem worse, leading to more drinking.

Sleep disruption is significant even though alcohol can help you fall asleep. Alcohol suppresses REM sleep, which is essential for feeling rested. This is why you can sleep 8 hours after drinking and still wake up feeling tired. The effects on sleep quality can persist for several days after heavy drinking.

Cognitive decline occurs with chronic heavy drinking. Problems with memory, attention, and decision-making can persist even during periods of sobriety. In severe cases, chronic alcohol use leads to Wernicke-Korsakoff syndrome, a serious neurological condition that causes confusion, memory problems, and coordination difficulties.

Who Faces the Greatest Risks

While alcohol poses dangers to anyone who drinks, certain groups face higher risks.

Heavy drinkers face the most significant dangers. The CDC defines heavy drinking as 15 or more drinks per week for men and 8 or more for women. At these levels, liver disease, cancer, and cardiovascular problems become substantially more likely.

Binge drinkers also face elevated risks. Binge drinking is defined as 5 or more drinks for men or 4 or more for women within about 2 hours. This pattern puts immediate stress on the heart and liver even in people who don't drink daily.

People with genetic predisposition may be more vulnerable. Some people metabolize alcohol differently due to genetic variations, affecting both cancer risk and likelihood of developing dependence.

Older adults face greater risks because the body processes alcohol less efficiently with age. The same amount of alcohol produces higher blood alcohol levels in older adults compared to younger people.

People with existing health conditions like liver disease, heart problems, or diabetes may experience accelerated harm from alcohol.

Can Alcohol Damage Be Reversed?

One of the most important points about the dangers of alcohol is that much of the damage can improve or reverse if drinking stops.

Brain function often improves substantially with abstinence. Research suggests that within 12 months of stopping drinking, most cognitive improvements occur. The brain has significant capacity for healing, though some effects of severe, long-term use may be permanent.

Liver recovery depends on the stage of damage. Fatty liver can reverse completely within weeks. Alcoholic hepatitis can improve significantly. Cirrhosis is permanent, but stopping drinking prevents further damage.

Cardiovascular health typically improves with reduced drinking. Blood pressure often decreases within weeks. Heart function can improve over months of abstinence.

Cancer risk decreases gradually after stopping, though former drinkers may have somewhat elevated risk compared to never-drinkers for many years.

For information on what happens when you stop drinking, our article on how long alcohol withdrawal lasts covers the initial timeline.

Reducing Your Risk

Understanding the dangers of alcohol leads naturally to the question of what to do about them.

Reducing consumption lowers health risks. Following moderate drinking guidelines, which means up to 1 drink per day for women and up to 2 for men, reduces risk compared to heavier drinking.

Taking breaks from alcohol gives your body time to recover. Even a month without drinking produces measurable improvements in liver function, blood pressure, and sleep quality.

Medication-assisted treatment helps if you're finding it difficult to cut back on your own. Naltrexone is an FDA-approved medication that reduces alcohol cravings and the rewarding effects of drinking.

Naltrexone works by blocking opioid receptors in the brain. When these receptors are blocked, alcohol doesn't produce the same dopamine surge that makes drinking feel pleasurable. Over time, this breaks the association between alcohol and reward, reducing the desire to drink. The medication is taken as a daily 50mg tablet and is safe to use whether or not you end up drinking on a given day.

Our article on how naltrexone helps you regain control explains the medication in more detail.

Taking the Next Step

The dangers of alcohol are well-documented, but they're also largely avoidable. Whether you want to cut back, take a break, or stop entirely, options exist to help you protect your health.

Take the online Alcohol Use Assessment to learn more about your drinking patterns and see if naltrexone could help you reduce your risk.