Introduction Capecitabine is an orally administered prodrug that converts preferentially to 5-fluorouracil within tumors, resulting in enhanced concentrations of 5-fluorouracil in tumor tissue. The use of capecitabine has shown efficacy in the metastatic setting for breast cancer, and more recently, efficacy as adjuvant therapy for triple-negative breast cancer (TNBC). Capecitabine has been shown to be well tolerated with minimal side effects, but the incidence of leukoencephalopathy is rare with a risk of less than one percent. Case report We report on a 34-year-old female patient with left TNBC, moderately differentiated, stage IIB that experienced symptoms of neurotoxicity following initiation of adjuvant chemotherapy with capecitabine. Management and outcome Naranjo Algorithm Assessment score of nine indicated patient had drug-induced leukoencephalopathy leading to discontinuation of capecitabine and resolution of the neurotoxicity symptoms. Discussion Early detection of capecitabine-induced neurotoxicity by magnetic resonance imaging is crucial as symptoms may be reversible to the condition that capecitabine is immediately discontinued.