BACKGROUND: Treating vaso-occlusive painful crises in people with sickle cell disease is complex and requires multiple interventions. Extra fluids are routinely given as adjunct treatment, regardless of the individual's state of hydration with the aim of slowing or stopping the sickling process and thereby alleviating pain. This is an update of a previously published Cochrane Review. OBJECTIVES: To determine the optimal route, quantity and type of fluid replacement for people with sickle cell disease with acute painful crises. SEARCH METHODS: We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register which comprises of references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings.We also conducted searches of Embase (November 2007), LILACS, www.ClinicalTrials.gov (05 January 2010), and the WHO ICTRP (30 June 2017).Date of most recent search of the Group's Haemoglobinopathies Trials Register: 16 February 2017. SELECTION CRITERIA: Randomised and quasi-randomised controlled trials that compared the administration of supplemental fluids adjunctive to analgesics by any route in people with any type of sickle cell disease during an acute painful episode, under medical supervision (inpatient, day care or community). DATA COLLECTION AND ANALYSIS: No relevant trials have yet been identified. MAIN RESULTS: Sixteen trials were identified by the searches, all of which were not eligible for inclusion in the review. AUTHORS' CONCLUSIONS: Treating vaso-occlusive crises is complex and requires multiple interventions. Extra fluids, generally oral or intravenous, are routinely administered during acute painful episodes to people with sickle cell disease regardless of the individual's state of hydration. Reports of their use during these acute painful episodes do not state the efficacy of any single route, type or quantity of fluid compared to another. However, there are no randomised controlled trials that have assessed the safety and efficacy of different routes, types or quantities of fluid. This systematic review identifies the need for a multicentre randomised controlled trial assessing the efficacy and possible adverse effects of different routes, types and quantities of fluid administered to people with sickle cell disease during acute painful episodes.