Alcohol poisoning happens when someone drinks more alcohol than their liver can break down, allowing toxic levels to build up in the bloodstream. The average person’s liver processes about 7 grams of alcohol per hour, roughly equal to one standard drink. Anything faster than that pace causes blood alcohol concentration (BAC) to climb, and at high enough levels, alcohol begins shutting down the brain’s ability to control basic survival functions like breathing and heart rate.
Why Drinking Speed Matters Most
The single biggest factor in alcohol poisoning is how fast someone drinks. Your liver works at a relatively fixed speed, so four drinks spread over four hours is a fundamentally different situation than four drinks in one hour. In the first scenario, the liver mostly keeps pace. In the second, alcohol floods the bloodstream faster than the body can clear it, and BAC spikes.
Binge drinking is the pattern most closely tied to alcohol poisoning. The NIAAA defines it as reaching a BAC of 0.08% or higher, which typically corresponds to five or more drinks for men or four or more drinks for women in about two hours. But alcohol poisoning occurs well beyond that threshold. As BAC continues to climb past binge levels, the risks escalate from blackouts to loss of consciousness to death.
What counts as a “standard drink” often surprises people. It’s any beverage containing 0.6 fluid ounces (14 grams) of pure alcohol. That’s one 12-ounce beer at 5% alcohol, one 5-ounce glass of wine, or one 1.5-ounce shot of distilled spirits. A strong cocktail at a bar can easily contain two or three standard drinks in a single glass, meaning someone who has “just three drinks” may actually consume six or more standard units without realizing it.
How Alcohol Reaches Dangerous Levels
Alcohol is absorbed slowly from the stomach but rapidly from the small intestine. The speed at which your stomach empties its contents into the small intestine is one of the biggest variables in how quickly you feel the effects. When the stomach empties fast, absorption is fast, and BAC peaks higher and sooner. When it empties slowly, peak blood alcohol levels are lower and more delayed.
This is why drinking on an empty stomach is so dangerous. Food in the stomach slows gastric emptying, which acts as a natural brake on absorption. Without food, alcohol passes quickly into the small intestine and floods the bloodstream. Carbonated mixers can also speed up gastric emptying, pushing alcohol into the intestine faster. These differences in absorption help explain why two people drinking the same amount can end up at very different BAC levels.
Body size, biological sex, hydration, and individual enzyme activity all play a role too. People with smaller body mass have less blood volume to dilute the alcohol. Women generally produce less of the stomach enzyme that begins breaking down alcohol before it reaches the bloodstream, which means more alcohol enters circulation at full strength.
Medications That Lower the Threshold
Certain medications make alcohol poisoning possible at amounts that might otherwise be survivable. Some drugs amplify alcohol’s depressant effects on the brain. Others interfere with the enzymes that break alcohol down, causing higher blood alcohol levels from the same number of drinks.
The most dangerous combinations involve anything that also sedates the central nervous system. Prescription sleep aids, anti-anxiety medications (benzodiazepines), opioid painkillers, barbiturates, and sedating antihistamines all enhance alcohol’s ability to suppress breathing and consciousness. With benzodiazepines and barbiturates specifically, the combined effect can be synergistic, meaning the two together are more dangerous than you’d expect from simply adding their individual effects.
Even common over-the-counter medications can change the equation. Aspirin and certain heartburn drugs can inhibit alcohol metabolism in the stomach lining, resulting in higher BAC from a given amount of alcohol. Tricyclic antidepressants increase sedation when combined with drinking. The list of interacting drug classes is long: antibiotics, antidepressants, muscle relaxants, anti-inflammatory medications, and blood thinners all interact with alcohol in various ways.
What Happens in the Body During Alcohol Poisoning
Alcohol is a central nervous system depressant. At moderate levels it impairs coordination and judgment. At poisoning levels, it starts suppressing the brainstem, the area responsible for automatic functions you don’t consciously control.
Breathing slows to fewer than eight breaths per minute, or becomes irregular with gaps of more than 10 seconds between breaths. Body temperature drops because alcohol dilates blood vessels and impairs the body’s ability to regulate heat. This hypothermia can become severe enough to trigger cardiac arrest. Heart rhythm becomes erratic and blood pressure can drop to dangerous levels, which in turn causes the heart to beat faster in a failing attempt to compensate.
One of the most immediate threats is choking. Alcohol suppresses the gag reflex, so someone who vomits while unconscious can aspirate the vomit into their lungs. This can cause suffocation or, if they survive, a severe lung infection. Seizures are another risk, driven by the way alcohol disrupts the brain’s electrical signaling and drops blood sugar levels.
A critical point that many people don’t realize: BAC can keep rising even after someone stops drinking or passes out. Alcohol sitting in the stomach hasn’t been absorbed yet, so a person who seems “just drunk” can deteriorate rapidly as that remaining alcohol enters the bloodstream over the following 30 to 60 minutes.
Who Is Most Vulnerable
Young adults and college-age drinkers face high risk because of drinking games, peer pressure, and inexperience with their own limits. But alcohol poisoning isn’t limited to any age group. About 61,000 deaths per year in the U.S. are linked to binge drinking or drinking too much on a single occasion, a category that includes alcohol poisonings, alcohol-involved drug overdoses, motor vehicle crashes, and suicides. Overall, excessive alcohol use causes roughly 178,000 deaths annually in the U.S., a figure that increased 29% compared to just a few years earlier.
People with lower body weight, those who rarely drink (and therefore lack any built-up enzyme tolerance), and anyone taking sedating medications are at elevated risk. Older adults metabolize alcohol more slowly and are more likely to be on interacting prescriptions, making them quietly vulnerable even at moderate drinking levels.
Recognizing the Warning Signs
The signs that distinguish alcohol poisoning from ordinary drunkenness are:
- Breathing changes: fewer than eight breaths per minute, or gaps longer than 10 seconds between breaths
- Unconsciousness: the person cannot be woken up, or wakes briefly but is incoherent
- Hypothermia: skin feels cold or clammy, possibly with a bluish tint, especially around the lips or fingertips
- Vomiting while passed out: especially dangerous because of the suppressed gag reflex
- Seizures
- Irregular heartbeat
If someone shows any of these signs, this is a medical emergency. Placing an unconscious person on their side (the recovery position) can help prevent choking while waiting for help. The instinct to “let them sleep it off” is the most dangerous mistake bystanders make, because BAC may still be climbing and breathing can stop without any outward warning.