For children with acute infectious diarrhoea, the recommended rehydration strategy is to use low-osmolarity oral rehydration salt (ORS) solution (240–250 mOsm/l) for oral rehydration therapy (ORT), administering 50 ml/kg for fluid deficit replacement over 4 hours along with maintenance fluids, and giving ORS frequently and in small amounts NICE 2009Shane 2017 NICE CKS,NICE CG84.
In children with clinical dehydration, including hypernatraemic dehydration, ORS solution should be used to rehydrate, with 50 ml/kg given over 4 hours, and the response monitored regularly NICE 2009Shane 2017 NICE CKS,NICE CG84.
For adults, the WGO guidelines recommend oral rehydration therapy (ORT) as a cost-effective method, emphasizing the use of low-osmolarity ORS solutions, and advise against fruit juices and carbonated drinks as they are hyperosmolar and can worsen diarrhoea symptoms Farthing 2012 NICE CKS.
Both children and adults should be encouraged to continue breastfeeding and normal fluid intake during rehydration, and solid foods should be reintroduced after initial rehydration NICE 2009Shane 2017 NICE CKS,NICE CG84.