Dehydration after stroke is associated with poor health outcomes, increased mortality and poses a significant economic burden to health services, yet research suggests that monitoring and assessment of hydration status is not routinely undertaken. This commentary critically appraises a systematic review which aimed to synthesise the existing evidence regarding diagnosis and treatment of dehydration after stroke. The review discusses common measures of dehydration, describes studies evaluating rehydration treatments, and highlights the link between dehydration and poorer health outcomes in both human and animal studies. The reviewers suggest that future research should focus on determining a single, validated, objective measure to clinically diagnose dehydration in stroke patients. Research designs should include clearly defined patient characteristics, type and severity of stroke, and type and time point of dehydration measurement, to enable comparison between studies. Management of hydration status is a crucial element of acute stroke care which should be routinely practiced. Commentary on Bahouth MN, Gottesman RF, Szanton SL. Primary ‘dehydration’ and acute stroke: a systematic research review. J Neurol. 2018;265(10):2167-2181. 10.1007/s00415-018-8799-6