According to the NIH, about 275 000 patients receive treatment with 5-Fluorouracil (5-FU) and more than 1300 die from 5-FU toxicity every year from life-threatening myelosuppression, gastrointestinal complications, and neurotoxicity. Immunocompromised persons are at higher risk of developing toxicity. Recently uridine triacetate (Vistagard®) has been approved by the Food and Drug Administration (FDA) as the only specific antidote available for 5-FU poisoning. In a clinical trial (n = 135), 96% of patients with 5-FU toxicity recovered after treatment, where as in a historical control group only 10% survived. This is the first published case report of survival after 5-FU overdose who also was immunocompromised from HIV/AIDs. A 52 year old male with history of HIV/AIDS (CD4 70), CNS toxoplasmosis and anal cancer presented to the emergency department after realizing he had received an entire course of 5-FU in 24 instead of 96 h. Treatment with uridine triacetate was arranged in the emergency department. After receiving treatment the patient was asymptomatic and had an uncomplicated hospital course. 5-FU poisoning must be recognized early as uridine triacetate is approved by the FDA for use within 96 h following the end of 5-FU administration. Emergency medicine physicians should promptly recognize and treat 5-FU poisoning. However, this may be challenging as patients may not seek medical attention until many hours or several days after last administration since symptoms are often delayed with 5-FU poisoning.