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Does drinking "flat" cola prevent dehydration in children with acute gastroenteritis?

Three Part Question

In [children with viral gastroenteritis] do [flat fizzy drinks such as coca cola compared to Oral Rehydration Solution] offer [adequate

Clinical Scenario

You are the registrar on duty in the Children’s Emergency Department. A registered children’s nurse asks you about an 18-month-old child who came in with his parents. He has been vomiting for the last 24 hours and has today developed loose watery
diarrhoea. His mother is concerned that his oral intake is poor and his nappies are not as wet as normal. The GP prescribed some Oral Rehydration Solution (ORS) yesterday but the child is refusing to drink it. A neighbour told the mother that allowing the child to drink “flat” cola was a good way to prevent him from getting dehydrated. The nurse asks you if this is a safe and acceptable treatment to recommend for children. You have heard it mentioned by parents of children with gastroenteritis before but feel unsure whether any evidence supports it.

Search Strategy

Primary searching used the dialog DataStar interface Medline 1950 to date, CINAHL(R) 1982 to date and EMBASE 1974 to date (search date: 18th April 2007).

A secondary search was performed on The Cochrane Library (Issue 2 2007) using the following terms: [gastroenteritis AND treatment], [gastroenteritis AND carbonated drink$], [gastroenteritis AND cola] and gastroenteritis AND flat cola]. Three articles were found but none was relevant to this question.
Two search strategies were run, firstly [gastroenteritis (textword) or (MeSH term)] AND [coca cola or or cola or fizzy drink$] yielding 25 records. Secondly [coca cola or or cola or fizzy drink$] AND [dehydrat$] OR [rehydrat$] yielding 9 records all of which were found by the first strategy. From these, 9 papers were relevant and reviewed. A further 5 relevant papers not picked up by initial searching were found from the articles reviewed.

Search Outcome

It is difficult to know what terms to choose in order to find all possible literature relating to such drinks, however the terms used were felt to be exhaustive. Repeated searches using alternative terms yielded no new papers and all the papers found by the initial search. Papers were mainly opinion or letters offering personal experience. One randomised controlled trial was found, but only in a published abstract; the full study could not be found. Several biochemical analyses-based papers and recommendations were found which alluded to the use of carbonated drinks in children with acute gastroenteritis. An analysis of this data was included. The table shows an appraisal of the single randomised trial.

Relevant Paper(s)

Author, date and country Patient group Study type (level of evidence) Outcomes Key results Study Weaknesses
Feldman et al,
110 infants Mean ages: Oral Electrolyte Solution (OES) group - 8.7 months, Unspecified clear fluid group – 10.5 months. Randomised controlled trial comparing Oral Electrolyte Solutions to unspecified clear fluids (including fruit juices, carbonated beverages, liquid gelatine, weak tea and water.RCT. Level of evidence 1b (details of randomisation not available)OES group - ingested larger volume of fluids, had fewer treatment failuresNo difference in purge rate, time to onset of solids, time of discharge 36-hour serum electrolyte levels and causative pathogens did not differ between groups.More detail on methodology not available; only abstract reported, full study not available.

Limitations: although a reasonable number of subjects, control group includes a fixture of different fluids and not specifically or singularly “flat” carbonated fluid.


No good quality controlled randomised trails were found. There were a small number of relevant papers, but none published in recent years. Those relevant to the clinical scenario were mainly offering opinion.

However, of importance, papers relating to the scientific analysis of the biochemical constituents of various liquids, both physiological (for example, ORS) and nonphysiological (for example, carbonated drinks), were found. The issue of biochemical composition of the carbonated drinks compared to ORS is relevant in the management of a mildly dehydrated child. The biochemical analyses clearly show the low levels of sodium (1.0 - 9.9mmol/litre) and potassium (0 - 0.3mmol/litre) and the very high osmolality (388 - 790 mOsm/kg of water) of various carbonated drinks (Dibley, Guignard, Nurses drug alert 1983, Nederlands Tijdschrift voor Geneeskunde 1982, Head). WHO recommendations are for oral rehydration solutions to contain 90 mmol/litre of sodium, 20 mmol/litre of potassium and 333 mOsm/kg of water. (Dibley) Also of note, although not consistently reported in biochemical data, is the amount of glucose in such drinks. Branded cola contains approximately 550 mmol/l while WHO ORT contains 111mmol/l as carbohydrate. (Dibley, American Academy of Pediatrics) It is concluded that there is little direct clinical data to answer this question but many scientific analyses demonstrating the inappropriateness of non-physiological liquids for treatment of acute gastroenteritis in children, compared with physiologically-based oral rehydration solutions. Therefore carbonated drinks, “flat” or otherwise, including cola, provide inadequate fluid replacement and cannot be recommended.

Editor Comment

Acknowledgements: Dr Bharat Patel, Consultant Biochemist, Watford General Hospital for analysing a sample of Coca Cola. Janet Reynolds, Librarian, Watford General Hospital for advice regarding literature searches.

Results from biochemical analysis of various carbonated drinks from selected studies compared to Oral Rehydration Solution available on ADC site. maxtoshow=&HITS=10&hits=10&RESULTFORMAT=1&author2=jacobs+m&andorexacttitle=and&andorexacttitleabs=and&andorexactfulltext=and&searchid=1&FIRSTINDEX=0&sortspec=relevance&resourcetype=HWCIT,HWELTR

Clinical Bottom Line

Limited clinical evidence plus much biochemical analysis suggests that carbonated drinks, such as cola (whether “flat” or otherwise) should not be recommended for oral rehydration in children with acute viral gastroenteritis.

Parents and carers should be discouraged from using “flat” fizzy drinks for this purpose.


  1. No authors listed. Acute diarrhoea in infants: oral rehydration is crucial. 2000 Oct;9(49):146-53.
  2. Hefelfinger DC. More on cola drinks and rehydration in acute diarrhea. N Engl J M 1987 Jan 29; 316(5):280.
  3. Weizman Z.N. Cola drinks and rehydration in acute diarrhea. N Engl J Med. 1986;Sep 18; 315(12):768.
  4. Dibley M, Phillips F, Mahoney T J, Berry R J. Oral rehydration fluids used in the treatment of diarrhoea. Analysis of the osmolalities, and sodium, potassium and sugar contents of commercial and home-made products. The Medical Journal of Australia 1984; 140(6):341-7.
  5. Guignard JP. Potassium in coca-cola. Lancet. 1983 Feb 26; 1(8322):474.
  6. No authors listed. Cola drinks not recommended for diarrhea. Nurses' Drug Alert 1987 Jan;11(1): 4.
  7. No authors listed. Coca-Cola is not for diarrhea...should not be used for potassium replacement in infant diarrhea. Nurses' Drug Alert, 1983 Jul; 7(7): 53.
  8. Weitzman Z, Mozes S. Electrolyte content and osmolality of Israel soft drinks and their unsuitability for oral rehydration in infantile diarrhea. Harefuah. 1987 Feb 15; 112(4):174-5.
  9. No authors listed. Is coca-cola suitable for rehydration of very young children with diarrhea? Nederlands Tijdschrift voor Geneeskunde 1982; 126(34): 1557-1558.
  10. American Academy of Pediatrics, Provisional Committee on Quality Improvement, Subcommittee on Acute Gastroenteritis. Practice parameter: the management of acute gastroenteritis in young children. Pediatrics 1996;97(3):424-35.
  11. Feldman W, Pennie R, Ritter H. Oral electrolyte solutions vs unspecified clear fluids in the management of mild gastroenteritis in infants. Am J Dis Child 1986; 140-303. Abstract.
  12. Klish WJ. Use of oral fluids in treatment of diarrhea. Paeditrics in Review – AAP 1985; 1:27-30.
  13. Listernick R, Zieseri E, Davis AT. Outpatient oral rehydration in the United States. Am J Dis Child 1986; 140:211-5.
  14. Head J, Hogarth M, Parsloe J, Broomhall J. Soft drinks, electrolytes and sick children. Lancet 1983; 1:1450.