Cannabis overdose symptoms include severe anxiety or panic, paranoia, a racing heart, nausea and vomiting, dizziness, confusion, and extreme drowsiness. A cannabis overdose, often called greening out, is rarely fatal in healthy adults, but it can be deeply distressing, trigger short-term psychosis, and send people to the emergency room. Chest pain, seizures, trouble breathing, or unresponsiveness means emergency care right away.
Symptoms of a Cannabis High: Effects, Timing, and What Helps
Does cannabis actually cause overdose?
Yes, in the sense that consuming too much THC can make you acutely and seriously ill. No, in the sense that cannabis alone has not been linked to fatal overdose in healthy adults the way opioids or alcohol are. The risk profile changes with edibles, high-potency concentrates, contaminated products, and synthetic cannabinoids.
What are the most common cannabis overdose symptoms?
- Extreme anxiety, panic, or a sense of impending doom
- Paranoia and suspiciousness
- Fast heart rate and rising blood pressure
- Nausea, vomiting, and stomach pain
- Dizziness, lightheadedness, or fainting
- Confusion, disorientation, and poor coordination
- Slurred speech and slowed reactions
- Heavy drowsiness or trouble staying awake
- Chills, sweating, and shaking
- Hallucinations or distorted sense of time
Why do edible overdoses hit harder?
Edibles take 30 minutes to 2 hours to produce effects, and peak effects often arrive around 3 to 4 hours. People who feel nothing quickly eat more, stacking doses and creating intense symptoms that can last 6 to 12 hours or longer. THC metabolites are fat soluble, so effects can linger well past the point where a person expects relief.
Green Out Effects: What Happens When You Take Too Much THC
When is a cannabis overdose an emergency?
- Chest pain or a heartbeat that will not slow down
- Seizures or convulsions
- Slow, shallow, or labored breathing
- Unresponsiveness or inability to wake the person
- Repeated vomiting or signs of dehydration
- Suicidal thoughts, agitation, or violent behavior
- Any symptoms in a child, older adult, pregnant person, or someone with heart disease
Call 911 or Poison Help at 1-800-222-1222 for guidance. Poison control can advise on home monitoring versus a hospital visit, and calls are free and confidential.
Symptoms of a Cannabis Overdose: What to Expect and When to Get Help
Who is at higher risk of a bad reaction?
First-time users, children who eat a parent's edible, and people taking high-dose THC concentrates face the highest risk. Combining cannabis with alcohol, benzodiazepines, or opioids multiplies impairment and sedation. A history of psychosis, bipolar disorder, or panic disorder also raises the odds of a severe psychiatric reaction.
Can CBD cause an overdose?
CBD has a wide safety margin and does not produce the intoxication linked to THC. Large doses may cause drowsiness, diarrhea, nausea, and appetite changes, and CBD can raise blood levels of some prescription medications by affecting liver enzymes. Because CBD products are not reviewed by the FDA before sale, mislabeling is a real risk, and some items sold as CBD contain THC or synthetic cannabinoids.
How is a cannabis overdose treated?
Most cases need only supportive care: a calm, quiet space, reassurance, fluids, and time. Emergency treatment may include IV fluids, anti-nausea drugs, benzodiazepines for severe agitation, and monitoring of heart rhythm and breathing. Symptoms typically ease within a few hours, though psychosis and vomiting can persist longer.
How do you lower the risk?
- Start low and go slow, especially with edibles
- Wait at least 2 hours before taking a second edible dose
- Buy lab-tested products with a certificate of analysis so you know the actual potency
- Avoid mixing cannabis with alcohol or sedatives
- Store edibles locked away from children and pets
Frequently asked questions
Can you die from a cannabis overdose?
Death from cannabis alone is extremely unlikely in healthy adults. Fatal outcomes are usually tied to contaminated products, synthetic cannabinoids, or mixed substance use.
How long do cannabis overdose symptoms last?
Smoked or vaped effects usually fade in 1 to 3 hours. Edible symptoms commonly last 6 to 12 hours, and residual grogginess can stretch into the next day.
What does greening out feel like?
People describe sudden sweating, chills, nausea, a pounding heart, dizziness, and overwhelming panic. Lying down in a quiet room and sipping water often helps, but severe cases need medical care.