Psychedelic film 25I-NBOMe (2C-I-NBOMe, Cimbi-5, and also shortened to "25I"), also known as Smiles, or N-Bomb, is a novel synthetic psychoactive substance with strong hallucinogenic properties, synthesized in 2003 for research purposes.

It was discovered in 2003 by chemist Ralf Heim at the Free University of Berlin, who published his findings in his PhD dissertation.

[14] For sublingual and buccal administration, 25I-NBOMe is often applied to sheets of blotter paper of which small portions (tabs) are held in the mouth to allow absorption through the oral mucosa.

[21] At this level of potency, it is not possible to accurately measure a single dose of 25I-NBOMe powder without an analytical balance, and attempting to do so may put the user at significant risk of overdose.

One study has shown that 25I-NBOMe blotters have 'hotspots' of the drug and the dosage is not evenly applied over the surface of the paper, which could lead to overdose.

[14] Case reports of seven British males who presented to an emergency room following analytically confirmed 25I-NBOMe intoxication suggest the following potential adverse effects: "tachycardia (n = 7), hypertension (4), agitation (6), aggression, visual and auditory hallucinations (6), seizures (3), hyperpyrexia (3), clonus (2), elevated white blood cell count (2), elevated creatine kinase (7), metabolic acidosis (3), and acute kidney injury (1).

"[18] 25I-NBOMe can be consumed in liquid, powder or paper form and can be snorted, injected, mixed with food, or smoked, but sublingual administration is most common.

[26] Reports of autonomic dysfunction remains prevalent with NBOMe compounds, with most individuals experiencing sympathomimetic toxicity such as vasoconstriction, hypertension and tachycardia in addition to hallucinations.

[27][28][29][30][31] Other symptoms of toxidrome include agitation or aggression, seizure, hyperthermia, diaphoresis, hypertonia, rhabdomyolysis, and death.

[26] NBOMe and NBOHs are regularly sold as LSD in blotter papers,[25][33] which have a bitter taste and different safety profiles.

[41][42][43] The high affinity of NBOMe compounds for adrenergic α1 receptor has been reported to contribute to the stimulant-type cardiovascular effects.

[26] 25C-NBOMe, including the other derivative 25D-NBOMe, reduced the visibility of cardiomyocytes H9c2 cells, and both substances downregulated expression level of p21 (CDC24/RAC)-activated kinase 1 (PAK1), an enzyme with documented cardiac protective effects.

The website Erowid states that 25I-NBOMe is extremely potent and should not be snorted, and that the drug "appears to have led to several deaths in the past year.

[47] A 21-year-old man from Little Rock, Arkansas died in October 2012 after taking a liquid drop of the drug nasally at a music festival.

[48] In January 2013, an 18-year-old in Scottsdale, Arizona, died after consuming 25I-NBOMe sold as LSD; a toxicology screening found no other drugs in the person's system.

[51] In October 2015, a 20-year-old UCSB student from Isla Vista, California died of "acute hallucinogenic polysubstance intoxication" with an additional significant cause of death being "sharp force trauma of the upper extremity", according to a statement from Santa Barbara County Sheriff's office; the autopsy determined Sanchez was under the influence of two hallucinogenic drugs at the time of his death: ketamine and 25I-NBOMe.

The noted sharp force trauma refers to a deep cut on Sanchez's right forearm, which was caused when he punched and broke a large residential window while suffering hallucinations.

In March 2012, a man in Australia died from injuries sustained by running into trees and power poles while intoxicated by 25I-NBOMe.

[59] 25I-NBOMe induces a head-twitch response in mice which is blocked completely by a selective 5-HT2A antagonist, suggesting its psychedelic effects are mediated by 5-HT2A.

[60] 25B-NBOMe is a low-potency weak partial agonist of the rat and mouse trace amine-associated receptor 1 (TAAR1) but is inactive at the human TAAR1.

14 of 1995 criminalises production, import, export, transport, buying, selling, possessing, storing of narcotic and psychotropic substances (Including 25i-NBOMe) unless done so as part of supervised and regulated medical or scientific activities in accordance with the applicable laws.