How Long Does Greening Out Last?

Somewhere in the middle of a bad greening-out episode, the only question that matters is: when does this stop? The short answer is usually 20 minutes to an hour. The longer answer depends a lot on how you consumed the THC, and that gap is bigger than most people expect.

Smoking or vaping: the shortest ride

If you greened out from smoking or a vape pen, the acute wave — dizziness, cold sweats, nausea — typically peaks within 10 to 20 minutes and starts fading after that. Most people feel mostly normal within 30 to 60 minutes, though a lingering grogginess or mild queasiness can hang around for a couple hours after the worst has passed.

This tracks with how fast smoked THC hits the bloodstream through the lungs and how quickly blood THC concentration starts dropping once you stop inhaling.

Edibles: a much longer timeline

This is where things get less predictable. Edible THC has to go through digestion and the liver before it reaches your system, so it hits later and lingers longer. A greening-out episode from edibles can run:

• Onset: 30 minutes to 2 hours after eating (this is why people accidentally overdose — they take more, thinking the first dose didn’t work)
• Peak intensity: often 2 to 4 hours after eating
• Total duration of the acute phase: commonly 4 to 8 hours, sometimes longer with a very high dose
• Residual grogginess: can stretch into the next day

The liver converts THC into 11-hydroxy-THC, a byproduct that’s both more potent and slower to clear than regular THC, which is a big part of why edible episodes drag on so much longer than smoking.

What actually shortens it

There’s no way to instantly reverse it — your liver and kidneys process THC at their own pace regardless of what you do. But a few things can make the experience more bearable while you wait it out, covered in more detail in our guide on how to stop greening out: lying down somewhere cool, sipping water slowly, and having something starchy on hand if nausea allows for it.

When it’s taking longer than it should

If symptoms are still severe after several hours — not just lingering grogginess, but ongoing vomiting, chest pain, or confusion — that’s worth a call to poison control or a trip to urgent care. It’s rare for THC alone to cause that kind of extended reaction, which raises the question of whether something else is involved, whether that’s a much higher dose than intended, another substance mixed in, or dehydration from repeated vomiting.

There’s also a separate pattern worth knowing about: some long-term, heavy cannabis users develop repeated vomiting episodes that have nothing to do with a single high dose. If nausea and vomiting keep coming back regardless of how much you used that day, that’s a different issue covered in our guide to Cannabinoid Hyperemesis Syndrome.

FAQ

Can greening out last more than a day?

The acute symptoms rarely stretch past 8 to 10 hours, even from edibles. A day-plus of nausea and vomiting is more consistent with a very high edible dose combined with dehydration, or a separate underlying issue.

Does throwing up shorten it?

Not really, since edible THC is absorbed through the intestines, not sitting in the stomach for long. Vomiting can bring temporary relief from nausea but doesn’t meaningfully speed up recovery.

Why did it hit me so much harder than my friend who ate the same amount?

Body weight, metabolism, tolerance, and whether you ate on an empty stomach all change how fast and how intensely THC is absorbed. Two people eating the same edible can have very different experiences.

Written by the CHS SOS Team · Last updated: July 2026