We report a life-threatening reaction, possibly from topical 0.5% 5-fluorouracil cream, which is a lower strength dose than the only reported case of a life-threatening adverse event with 5.0% 5-fluorouracil cream.

Given the common use of topical 5-fluorouracil cream, it is important for clinicians to consider the adverse side effects that can occur, especially in patients with a dihydropyrimidine dehydrogenase deficiency.