When too much THC (tetrahydrocannabinol) is consumed too quickly, it can cause a person to feel acutely ill—a phenomenon commonly called “greening out.” To understand this reaction, we need to look at how THC impacts three major systems: the brain, heart, and stomach.

 

The Mind-Body Conflict: Brain vs. Heart

Your body is designed to reward itself with dopamine, a chemical that triggers feelings of pleasure. THC hijacks this system, triggering a massive, unnatural surge of dopamine that creates the intense feeling of euphoria, giddiness, or detachment associated with being high.

 

The Brain is Relaxed, But the Body is Stressed: While the mind is experiencing this intense chemical euphoria, the body is reacting with a physical stress response that is the opposite of relaxed. THC activates stress receptors, causing a spike in:

•Heart rate, sometimes by 20 to 50 beats per minute

•Blood pressure

•Adrenaline

 

The Result: Anxiety and Panic: For many users, especially those already prone to worry or panic, this sudden conflict between the euphoria and the physical distress is overwhelming. Your mind may feel “checked out,” but your body is screaming danger, leading to intense paranoia, panic attacks, and heightened anxiety.

 

Adding the Stomach and Digestive System

The stomach and digestive tract also have THC receptors that react strongly to a high dose of THC. When the body is overloaded with THC, the digestive system often reacts first.

 

This overload can lead to immediate physical symptoms like:

•Intense nausea

•Stomach discomfort or cramping

•Severe dizziness and heavy vomiting

 

For some people, this overwhelming dose is what specifically triggers the “greening out” episode. When this happens the person may look distinctly pale, greenish, or ashy. They may sweat and shake, experience nausea or vomiting, and have impaired coordination. They’ll feel disoriented, their heart rate will elevate, and their vision may blur.

 

A Serious Condition: Cannabinoid Hyperemesis Syndrome (CHS)

It’s important to note that regular, heavy use of high-potency THC products can lead to a serious and debilitating condition called Cannabinoid Hyperemesis Syndrome (CHS). This syndrome involves repeated cycles of uncontrollable vomiting and severe abdominal pain that can last for hours or days. A Cleveland Clinic study reported that 33% of cannabis users who came to an emergency department for care met the criteria for CHS. The only known cure is to completely stop using THC products.

 

 

 

Understanding the science behind THC consumption—specifically the onset, peak, and duration of different methods—is a great tool an adult can use to guide a young person. The reaction known as “greening out” is a critical, physical signal that the body’s major systems (brain, heart, and stomach) have been dangerously overloaded. Use this knowledge to emphasize that cutting down or quitting isn’t just about avoiding trouble; it’s about protecting their long-term mental and physical health from an overwhelming, unpredictable substance. Your guidance is the first step toward promoting safer choices and a healthier future.