Green out

A "green out" (UK: "whitey") is an acute adverse reaction to cannabis overconsumption characterized by pallor, sweating, nausea, dizziness, anxiety, tachycardia, orthostatic hypotension, and occasionally syncope. Mechanism involves CB1-mediated peripheral vasodilation with reflex tachycardia, producing orthostatic hypotension; vagally-mediated vasovagal response contributes, especially on standing (Mathew et al. 2003 Drug Alcohol Depend). Sathyan et al. and Jouanjus et al. have documented cannabis-associated cardiovascular events in susceptible individuals. In healthy adults, green outs are subjectively distressing but not medically dangerous and resolve spontaneously within 30 minutes to several hours. Harm-reduction management: recumbent or seated positioning, reassurance, hydration, cool environment, simple sugars if hypoglycemic. Risk factors: cannabis-naïve status, high-potency products, edibles, empty stomach, concurrent alcohol, standing posture, thin body habitus, and cardiovascular comorbidity (which merits medical evaluation). Folk remedies (black pepper, lemon) lack RCT support but are low-risk. Citations: Mathew RJ et al. Drug Alcohol Depend. 2003;71:173-180; Hall W, Degenhardt L. Lancet. 2009;374:1383-1391; Monte AA et al. Ann Intern Med. 2019;170:531-537.