Greening out: what it is and what to do if you get too high
What greening out means, the signs of too much cannabis listed by the CDC, how long it lasts, whether CBD helps, and when to call Poison Control or 911.
Key points
- Signs include anxiety, panic, a fast heart rate, and nausea or vomiting.
- Health agencies list no quick fix; the effects wear off with time.
- Poison Control: 1-800-222-1222. Emergency: 911.
Greening out is slang for feeling sick after too much cannabis. The CDC lists the signs as extreme confusion, anxiety, paranoia, panic, a fast heart rate, and severe nausea or vomiting. It passes with time. For advice, call Poison Control at 1-800-222-1222; in an emergency, call 911.
What is greening out?
"Greening out" is not a medical term. Health agencies describe the same thing as overconsumption or cannabis poisoning. The CDC puts it this way: "While a fatal overdose caused solely by cannabis is unlikely, cannabis is not harmless."
It is especially likely with edibles and drinks. They can take up to two hours to be felt, so people take more while they wait. Our edible dosage guide covers the timing.
What are the symptoms of greening out?
The CDC says the signs of using too much cannabis "are similar to the typical effects of using cannabis but more severe." Its list: extreme confusion, anxiety, paranoia, panic, a fast heart rate, delusions or hallucinations, increased blood pressure, and severe nausea or vomiting.
The CDC adds that these effects can lead to unintentional injury, such as a fall or a motor vehicle crash. Health Canada's list of immediate effects also includes dizziness or feeling faint, a dry mouth and drowsiness.
What should you do if you are too high?
The official guidance is short. If you or someone you know shows signs of having used too much cannabis, the CDC says to call a poison control center at 1-800-222-1222, and 911 in an emergency. CDC Poison Control is free and answers around the clock.
Beyond that, the same sources point to three things. Do not take more while you wait for it to pass. Do not add alcohol: the CDC says using alcohol and cannabis together is likely to cause greater impairment than either alone. And do not drive.
If a child has eaten a cannabis product, treat it as urgent. The CDC notes that children who consume THC can become very sick and may have trouble walking, sitting up or breathing.
How long does greening out last?
It depends on how the cannabis was taken. Health Canada gives these general figures for how long effects could last: Health Canada
| How it was taken | Effects could begin | Effects could last |
|---|---|---|
| Inhaled (smoked or vaped) | Seconds to minutes | 2 to 4 hours |
| Eaten or drunk | 30 minutes to 2 hours | 4 to 8 hours |
Health Canada adds that some lingering effects can last 12 to 24 hours.
Does CBD counteract THC?
The best controlled evidence says no. In a randomized, double-blind trial, 46 volunteers inhaled cannabis containing 10 mg of THC with 0, 10, 20 or 30 mg of CBD. The researchers "found no evidence of CBD reducing the acute adverse effects of THC on cognition and mental health."
Englund et al., Neuropsychopharmacology
The same paper notes that people may reduce harm by choosing products with a higher ratio of CBD to THC, but because that means less THC, not because of the CBD.
Common questions
Can you die from greening out?
The CDC says a fatal overdose caused solely by cannabis is unlikely, but that cannabis is not harmless: the effects can lead to injuries such as falls and crashes.
How do you sober up from weed fast?
None of the health agencies cited here list a way to speed it up. The effects wear off with time: generally 2 to 4 hours after inhaling and 4 to 8 hours after eating or drinking cannabis, according to Health Canada.
Does CBD help when you are too high?
A randomized trial published in Neuropsychopharmacology found no evidence that CBD reduced the acute adverse effects of THC, at any of the doses tested.
When should you call 911 for being too high?
The CDC says to call 911 in an emergency and Poison Control at 1-800-222-1222 for other cases. A child who has eaten a cannabis product, or anyone having trouble breathing, is an emergency.
Why do edibles cause greening out more often?
Because they are slow. The CDC says edibles can take from 30 minutes to 2 hours to be felt, so some people eat too much while waiting.
Sources and further reading
Kush is for adults 21+. This guide is educational; product rules and testing requirements vary by state. Our editorial standards & corrections policy.
