How Long Does a High Last After Vaping Cannabis?
Vaping cannabis usually hits in 2 to 10 minutes and fades over 1 to 3 hours. Here's how dry herb, cartridges, and dabs compare, plus what shifts the clock.
Yes, you can overdose on cannabis, but a cannabis overdose is rarely fatal. Here, overdose means taking in more THC than your body can process comfortably, which produces intense but usually temporary symptoms such as nausea, panic, and disorientation. The situations that turn dangerous involve children, edibles, mixing cannabis with other substances, or an underlying heart or mental health condition.
What a Cannabis Overdose Actually Means
The word overdose covers a wide range of events. With opioids, overdose means breathing slows until it stops. With cannabis, the term usually describes consuming too much THC and feeling severely uncomfortable, not dying. Clinicians often call this acute cannabis intoxication or cannabis toxicity. Most consumers know it as greening out.
Can Cannabis Kill You?
There are no confirmed reports of a fatal overdose from cannabis alone in adults. THC acts on receptors concentrated in the brain and nervous system, not in the brainstem areas that control breathing, so it does not shut down respiration the way opioids or heavy alcohol use can. That does not make a large dose harmless. Very high doses can cause severe vomiting, chest pain, a racing heart, and panic that feels like a heart attack. Cannabis becomes more dangerous when it is combined with alcohol, sedatives, or opioids, or when a person has an existing heart condition.
Signs You Have Taken Too Much
- Nausea and repeated vomiting
- Racing or pounding heartbeat
- Dizziness, feeling faint, or poor coordination
- Extreme anxiety, panic, or a sense of doom
- Confusion, disorientation, or slowed speech
- Paranoia or temporary hallucinations at very high doses
- Chills, sweating, or trembling
- Severe abdominal pain, which long-term heavy users may recognize as cannabinoid hyperemesis syndrome
Why Edibles Raise the Risk
Edibles cause more cannabis overdoses than inhaled products because the dose is easy to misjudge. Effects can take 30 to 120 minutes to peak, so people eat more because nothing has happened yet, then the full dose arrives at once. THC absorbed through the gut is also converted by the liver into 11-hydroxy-THC, a more potent form that can make the experience stronger and longer. A single serving is often 5 mg of THC, while one package may hold ten servings or more. Keep edibles labeled, sealed, and out of reach of children and pets.
Who Is Most at Risk
Young children who eat edibles are the group most likely to need emergency care, because a dose that is modest for an adult is large relative to a small body. Pets face the same problem, especially with chocolate edibles. Adults with heart disease, high blood pressure, or a personal or family history of psychosis should talk with a doctor before using high-THC products, since cannabis can raise heart rate and trigger temporary psychosis in susceptible people. Pregnant people are advised to avoid cannabis entirely.
What to Do If Someone Has Too Much
- Stay calm and stay with the person.
- Move to a quiet, safe space and sit or lie on one side to prevent choking if vomiting starts.
- Stop consuming more cannabis, alcohol, or other drugs.
- Sip water if the person is awake and able to swallow.
- Call Poison Control at 1-800-222-1222 for guidance, especially for a child.
- Call 911 for trouble breathing, chest pain, seizure, fainting, or unresponsiveness.
How to Lower Your Risk
- Start with 2.5 to 5 mg of THC and wait at least two hours before taking more.
- Read the label to confirm total THC per serving, not per package.
- Avoid mixing cannabis with alcohol or sedatives.
- Choose a lower-THC product if you are new to cannabis or sensitive to it.
- Store products in child-resistant containers, away from food packaging.
The Bottom Line
You can overdose on cannabis, and the experience can be frightening, but it is very rarely fatal for a healthy adult. The main risks are panic, vomiting, falls, and delayed care for symptoms that mimic a heart attack or stroke. Treat edibles with respect, keep them away from kids and pets, and call for help when symptoms go beyond feeling too high.