BACKGROUND Wernicke-Korsakoff syndrome (WKS) is a neuropsychiatric condition which results from thiamine deficiency, most commonly due to alcohol abuse. The prognosis of WKS is poor and its outcome depends mainly on prompt treatment. CASE REPORT A 52-year-old male with a ten-year history of heavy alcohol abuse was admitted in hospital and treated for WKS. Ataxic and oculomotor symptoms promptly reversed following standard treatment but no change was observed in higher mental functioning. Although the protracted WK symptoms made the patient's improvement unlikely, aggressive treatment with thiamine (600 mg/day orally and 300 mg/day intramuscularly) fully reversed the condition within two months. CONCLUSION Even though prolongation of undertreatment of WKS typically precludes significant improvement of symptoms due to irreversible damage of the brain, at least in some cases, higher thiamine doses (over 500 mg/day) for a longer period (at least three months) than usually recommended should be tried.