Careful assessment of the biochemistry panel and familiarity with normal biochemistry values for neonatal foals is imperative in the workup of any critically ill neonate, particularly those with neurological signs. The importance of rapidity of change compared to the absolute value of the biochemical abnormality must be emphasised. Serial biochemical panels ideally assist in assessing rapidity of change. Many foals can have severe biochemical derangements in the absence of seizures. Identifying values that are significantly out of range should spur immediate therapy to correct them and potentially additional diagnostic testing to determine the cause of the abnormalities. A temporal relationship between correction of biochemical abnormalities and resolution of seizures and encephalopathic signs supports causation.