Alcohol poisoning typically lasts several hours to more than a day, depending on how much was consumed and how quickly the body can clear the alcohol. The liver processes roughly one standard drink per hour, and nothing speeds that up. So if someone’s blood alcohol concentration (BAC) has climbed to dangerous levels, the body needs many hours just to metabolize the excess, and the symptoms and risks can persist well beyond that window.
Why BAC Keeps Rising After You Stop Drinking
One of the most dangerous aspects of alcohol poisoning is that blood alcohol levels can continue climbing even after a person stops drinking or loses consciousness. Alcohol sitting in the stomach and intestines keeps entering the bloodstream and circulating through the body. This means someone who seemed “just drunk” 30 minutes ago can deteriorate into a medical emergency without taking another sip.
This rising-BAC effect is especially pronounced when someone drinks a large amount in a short period, like during drinking games or binge episodes. The alcohol simply hasn’t had time to be absorbed yet. Peak BAC may not arrive until 30 to 90 minutes after the last drink, which is why the most critical window often starts after the drinking has already stopped.
The Danger Zone: BAC Levels That Matter
Alcohol poisoning generally occurs when BAC reaches 0.30% to 0.40%. At this range, loss of consciousness is likely and the condition becomes potentially life-threatening. Above 0.40%, the risk of coma and death from respiratory arrest (the body simply stops breathing) climbs sharply.
To put that in perspective, the legal driving limit in the U.S. is 0.08%. Alcohol poisoning territory is roughly four to five times that level. At one drink metabolized per hour, a person whose BAC reaches 0.35% would need many hours just for their liver to bring levels back below the danger threshold, and several more hours after that to approach zero.
How Long the Symptoms Last
The acute phase of alcohol poisoning, where the person is at highest risk, typically spans 6 to 12 hours. During this time, critical symptoms can include:
- Mental confusion or stupor
- Inability to stay conscious or be woken up
- Vomiting (especially dangerous when combined with an absent gag reflex)
- Seizures
- Slow breathing, fewer than 8 breaths per minute
- Irregular breathing, with gaps of 10 seconds or more between breaths
- Slow heart rate, clammy skin, and bluish or pale skin color
- Extremely low body temperature
Even after a person regains consciousness, they often feel severely ill for another 12 to 24 hours. Nausea, headache, confusion, and extreme fatigue can linger as the body continues processing the remaining alcohol and coping with dehydration and inflammation. A full return to normal can take one to three days depending on the severity of the episode.
What Happens at the Hospital
Hospital stays for alcohol poisoning vary but commonly last anywhere from a few hours of observation to overnight or longer if complications arise. The medical team focuses on keeping the person alive and stable while the body does the slow work of clearing the alcohol. Typical interventions include IV fluids to treat dehydration and restore blood sugar, oxygen delivered through a nasal tube, and in more serious cases, a breathing tube if the person can’t maintain their airway on their own.
In severe situations, doctors may pump the stomach to remove unabsorbed alcohol, or use blood filtration (dialysis) if the kidneys aren’t functioning properly. These measures don’t “cure” the poisoning. They buy time and prevent the most dangerous complications, like choking on vomit or organs shutting down from oxygen deprivation, while the liver works at its fixed pace.
Why Some People Are at Greater Risk
The timeline and severity of alcohol poisoning aren’t the same for everyone. Several factors determine how quickly someone reaches dangerous levels and how long recovery takes.
Body composition plays a significant role. Women tend to reach higher BAC levels faster than men of similar weight because of differences in body water content, body fat percentage, and hormone levels. People who are physically smaller or less muscular absorb alcohol into a smaller volume, which concentrates it more quickly. Whether you’ve eaten also matters: food in the stomach slows absorption by keeping alcohol in the stomach longer during digestion. Drinking on an empty stomach lets alcohol pass rapidly into the small intestine, where it’s absorbed much faster.
Fatigue, stress, medications, and overall health all amplify alcohol’s effects. Carbonated drinks speed absorption. Even altitude makes a difference: drinks consumed at high elevation can hit nearly twice as hard for the first few days before the body adjusts. None of these factors change how fast the liver clears alcohol, though. They just determine how high BAC climbs in the first place and how hard the body has to work on the way back down.
The Overnight Risk Most People Underestimate
The most dangerous scenario is when someone passes out after heavy drinking and is left to “sleep it off.” Because BAC can keep rising after the last drink, a person who falls asleep heavily intoxicated may slip from unconsciousness into a medical crisis without anyone noticing. Breathing can slow to dangerously low rates. The gag reflex can shut down, meaning vomiting while unconscious can lead to choking or inhaling vomit into the lungs. Body temperature can drop to dangerous levels.
This is why alcohol poisoning deaths often happen overnight or in the early morning hours. The critical period isn’t just the loud, visibly drunk phase. It’s the quiet hours afterward, when BAC is peaking and the body’s protective reflexes are suppressed. If someone is unconscious, can’t be woken, is breathing slowly or irregularly, or has cold and clammy skin, that’s a medical emergency right now, not something to reassess in the morning.