We present a case of inadvertent high-dose therapy with temozolomide in a child with recurrent diffuse intrinsic pontine glioma followed by a rapid clinical response. The patient was a 7-year-old boy who initially presented with a history of left facial palsy, double vision, headache, and ataxia. His symptoms were completely resolved following radiotherapy but recurred 3 months after. Following recurrence, he received temozolomide in a dose >3 times higher than prescribed inadvertently but tolerated well with a rapid clinical response. He eventually deteriorated after he was substituted with a lower dose of temozolomide and died.