A 20-year-old student presented with generalized tonic-clonic seizures and was diagnosed to have cortical venous thrombosis. Her dietary history and the clinical signs of vitamin deficiency prompted further investigations, which detected hyperhomocysteinaemia secondary to vitamin B12 deficiency as a factor contributing to the hypercoagulable state. This case highlights the importance of a balanced diet, as well as the necessity for primordial prevention.