Canavan disease is a rare autosomal recessive leukodystrophy characterized by abnormal accumulation of N-acetyl aspartate (NAA) in brain white matter. Currently, there is no cure for this disease, and management of patients consists mainly of treating symptoms. We describe a 3-month-old girl who was hospitalized for poor head control and decreased muscle tone. A battery of laboratory and genetic (homozygous mutation p.C218X) analysis revealed the presence of Canavan disease. Lithium citrate was initiated at a dosage of 45 mg/kg per day after diagnosis. Periodic controls of thyroid and liver function, and lithium levels in blood showed that this drug was sure and well tolerated. After 1 year of treatment, NAA levels decreased by approximately 20% in the brain region, urinary NAA levels showed a reduction of 80%, and patient improved alertness and visual tracking but continued with no heat support, axial hypotonia, and spastic diplegia. In our patient, the results obtained after drug administration are important with respect to the decrease in NAA and more discreet in clinical improvement. However, given the absence of adverse effects and limited treatment options, lithium citrate may be a good alternative to stop the progression of the disease and improve the quality of life of patients.