When you drink alcohol, it enters your bloodstream within minutes and begins affecting nearly every system in your body. Your liver can process roughly one standard drink per hour, and anything beyond that accumulates in your blood, progressively impairing your brain, coordination, and judgment. What happens next depends on how much you drink, how fast you drink it, and your individual biology.
How Alcohol Moves Through Your Body
Unlike most foods, alcohol doesn’t need to be digested. About 20% absorbs directly through your stomach lining, and the rest passes into your small intestine, where it enters the bloodstream rapidly. From there, it circulates to your brain, heart, muscles, and every other organ before the liver begins breaking it down.
Your liver metabolizes alcohol at a fixed rate of approximately one standard drink per hour. A standard drink is 12 ounces of beer, 4 ounces of wine, or 1.25 ounces of 80-proof liquor, all of which contain about half an ounce of pure alcohol. If you drink faster than your liver can keep up, the excess alcohol keeps circulating. That buildup is what intoxication actually is. There is no way to speed the process up. Not coffee, not cold showers, not food after the fact. Time is the only thing that clears alcohol from your system.
What Happens at Each Level of Intoxication
The effects of alcohol follow a predictable pattern tied to your blood alcohol concentration (BAC), the percentage of alcohol in your bloodstream.
- BAC 0.05% (roughly 2 drinks in an hour for an average person): You feel looser and more social. Alertness drops, and your judgment starts to slip in ways you may not notice.
- BAC 0.08% (the legal driving limit in most U.S. states): Muscle coordination declines noticeably. You have a harder time detecting danger, and reasoning becomes impaired.
- BAC 0.15%: Mood swings, nausea, vomiting, and loss of balance set in. Muscle control is significantly compromised.
- BAC 0.30% to 0.40%: This is alcohol poisoning territory. Loss of consciousness is likely, and the condition can be life-threatening.
- BAC over 0.40%: Risk of coma and death from respiratory arrest, where breathing simply stops.
These numbers shift based on body weight, sex, food in the stomach, and how quickly you’re drinking. A 130-pound person will reach a higher BAC from the same number of drinks than a 200-pound person.
What Alcohol Does to Your Brain
Alcohol works on two major communication systems in your brain simultaneously. First, it amplifies the activity of your brain’s main “slow down” signal, which normally keeps neural activity in check. This is what produces that relaxed, sedated feeling after a drink or two, and at higher doses, it causes the motor incoordination and slurred speech associated with being drunk.
At the same time, alcohol suppresses your brain’s primary “speed up” signal, the one responsible for alertness, learning, and memory formation. This suppression begins at surprisingly low concentrations, around a BAC of 0.03%, which is often below the point where you’d even feel tipsy. It’s a major reason why people experience blackouts or patchy memory after heavy drinking: your brain literally stops recording new memories.
Together, these two effects explain why alcohol is a depressant even though it initially feels stimulating. The early social buzz comes from lowered inhibitions, not from your brain being revved up. As BAC rises, the sedation becomes dominant.
Why Hangovers Happen
A hangover isn’t just dehydration, though that plays a role. The primary culprit is a toxic byproduct your liver creates while breaking down alcohol. Your liver converts alcohol into this intermediate compound before eventually converting it into harmless acetic acid. While that middle step is happening, the toxic intermediate circulates and contributes to headache, nausea, and general misery.
Darker liquors like bourbon, red wine, and brandy tend to produce worse hangovers than clear spirits like vodka. This is because of congeners, chemical byproducts of fermentation that are more concentrated in darker drinks. One congener in particular, methanol, gets broken down by the same liver enzymes as regular alcohol but produces an even more toxic byproduct: formaldehyde. Both compounds contribute to the severity of next-day symptoms.
The Alcohol Flush Reaction
Some people turn red in the face after even a small amount of alcohol. This flush reaction is caused by a genetic variation in one of the enzymes responsible for breaking down alcohol’s toxic byproduct. When that enzyme works poorly, the toxic intermediate builds up faster, triggering histamine release that causes facial redness, hives, nausea, low blood pressure, and sometimes migraine episodes or worsening asthma.
This variation is most common among people of East Asian ancestry. It’s more than a cosmetic nuisance. People who flush and continue to drink face a higher risk of esophageal and breast cancer, because the compound that accumulates in their blood is itself carcinogenic. If you consistently flush when you drink, that’s your body signaling it can’t process alcohol efficiently.
How Drinking Damages Your Liver Over Time
Repeated heavy drinking pushes the liver through a three-stage progression of disease. The first stage is fatty liver, where excess fat builds up because the liver is consistently processing more alcohol than it can handle. Fatty liver often has no symptoms and is reversible if drinking stops.
If it doesn’t stop, the fat triggers inflammation, the second stage. Chronic inflammation gradually damages liver tissue, and about 30% of people who reach this stage progress to the third: cirrhosis. Cirrhosis means the liver has scarred extensively enough that the damage can’t be undone. At that point, the liver’s ability to filter toxins, produce essential proteins, and regulate metabolism is permanently compromised.
The tricky part is that the liver rarely complains early. Many people with fatty liver or early inflammation feel fine, which makes it easy to underestimate the damage accumulating over years of regular heavy drinking.
How Much Is Too Much
The World Health Organization’s current position is blunt: since any alcohol use carries some short-term and long-term health risks, it’s difficult to define a universally safe threshold. This represents a shift from older guidelines that framed moderate drinking as relatively harmless. The risks include not just liver disease but cancers, cardiovascular problems, and mental health effects that begin at lower intake levels than many people assume.
In practical terms, the faster and more frequently you drink, the more damage accumulates. Binge drinking, typically defined as four or more drinks in a couple of hours for women and five or more for men, is particularly hard on the body because it overwhelms the liver’s fixed processing speed and exposes your brain and organs to sustained high concentrations of alcohol and its toxic byproducts.
A Note on Water
Since the search “what happens if you drink” is broad enough to include water: yes, you can also drink too much water. Consuming about a gallon (3 to 4 liters) in an hour or two can cause water intoxication, a condition where sodium levels in your blood drop dangerously low. Early symptoms include nausea, bloating, and headache. In severe cases, it progresses to confusion, muscle weakness, swelling, and changes in mental status. A safe general limit is no more than about a liter (32 ounces) per hour. If you feel nauseous or bloated while drinking water, stop.