BACKGROUND ThinPrep Cytolyt is a methanol-based cell preservation solution frequently used to fix tissue samples immediately following endobronchial ultrasound-guided fine-needle aspiration. Currently, no published reports describe an iatrogenic exposure to Cytolyt. We report the only known case of an accidental intraoperative administration of a methanol solution, with corresponding plasma concentrations, and successful treatment with fomepizole. CASE REPORT A 70-year-old woman with a history of stage IIIA rectal adenocarcinoma was referred for evaluation of a newly identified lung mass. During the procedure, a bronchoalveolar lavage (BAL) of the right upper lobe was performed. After BAL, the proceduralist was informed that the syringe used to instill fluid for the BAL contained Cytolyt rather than saline. The Department of Medical Toxicology was contacted immediately, and the patient received a 15 mg/kg dose of fomepizole. The first plasma methanol level, before fomepizole administration, was elevated to 21 mg/dL. The methanol level was 13 mg/dL 3 h after fomepizole treatment and even lower thereafter; therefore, no additional fomepizole was required. The patient did not develop signs of systemic toxicity and was discharged on hospital day 3. CONCLUSIONS Following methanol exposures, patients can exhibit metabolic acidosis, with potential for blindness, hemodynamic instability, and possibly death if untreated. Fomepizole (4-methylpyrazole) inhibits alcohol dehydrogenase and is a mainstay of treatment. Preventing medical errors is key in ensuring optimal patient care and decreasing adverse events. Providers using CytoLyt and any similar products should be aware of this potential error and approach the possibility of methanol toxicity as they would other routes of methanol exposure.