INTRODUCTION: 2C designer drugs have been in use since the 1970s, but new drugs continue to develop from substitutions to the base phenethylamine structure. This creates new clinical profiles and difficulty with laboratory confirmation. 2-(4-Iodo-2,5-dimethoxyphenyl)-N-[(2-methoxyphenyl)methyl]ethanamine (25I-NBOMe) is a relatively new 2C drug that is more potent than structural 2C analogs; exposure reports are rare. Testing for 2C drugs is developing; specific testing for new analogs such as 25I-NBOMe is a challenge. These drugs do not reliably trigger a positive result on rapid drug immunoassays. Additionally, most facilities with confirmatory testing capabilities will not identify 25I-NBOMe; methods for detecting 25I-NBOMe in biological samples have not been clearly described nor have optimal metabolic targets for detecting 25I-NBOMe ingestion. CASE REPORT: An 18-year-old female presented following use of 25I-NBOMe. She had an isolated brief seizure, tachycardia, hypertension, agitation, and confusion. She improved with intravenously administered fluids and benzodiazepines and was discharged 7 h postingestion. Urine was analyzed using quantitative LC-MS/MS methodology for 25I-NBOMe, 2-(4-chloro-2,5-dimethoxyphenyl)-N-[(2-methoxyphenyl)-methyl]ethanamine (25C-NBOMe), and 2-(2,5-dimethoxyphenyl)-N-(2-methoxybenzyl)ethanamine (25H-NBOMe). 25I-NBOMe was found at a concentration of 7.5 ng/mL, and 25H-NBOMe was detected as well. Additional testing was pursued to characterize the metabolism of 25I-NBOMe; the sample was reanalyzed with UPLC-time-of-flight mass spectrometry to identify excreted metabolites. The sample was additionally analyzed for the presence of 2,5-dimethoxy-4-iodophenethylamine (2C-I), 4-bromo-2,5-dimethoxyphenethylamine (2C-B), and 1-(2,5-dimethoxy-4-ethylphenyl)-2-aminoethane (2C-E). DISCUSSION: This is a report of a patient presenting following exposure to 25I-NBOMe, a dangerous member of the evolving 2C drug class. The exposure was confirmed in a unique manner that could prove helpful in guiding further patient analysis and laboratory studies.