By Ronald Steriti, ND, PhD

© 2013

Gastroenteritis is characterized by inflammation ("-itis") of the gastrointestinal tract that involves both the stomach ("gastro"-) and the small intestine ("entero"-), resulting in some combination of diarrhea, vomiting, and abdominal pain and cramping.

Gastroenteritis has also been referred to as gastro, stomach bug, and stomach virus. Although unrelated to influenza, it has also been called stomach flu and gastric flu.

Eosinophilic gastroenteritis (EG) typically presents with a combination of chronic nonspecific gastrointestinal symptoms that include abdominal pain, nausea, vomiting, diarrhea, weight loss, and abdominal distension. Approximately 80% of the patients have symptoms for several years. (Agrawal, Rani et al. 2012)


Norovirus is and the leading cause of gastroenteritis worldwide, and the leading cause of adult gastroenteritis in the United States. (Koo, Ajami et al. 2010)

Rotavirus is the leading cause in children. (Elliott 2007)

Non-infectious gastroenteritis can be caused by medications (i.e. NSAIDs), certain foods such as lactose (in those who are intolerant), and gluten (in those with celiac disease). Crohn's disease is also a non-infection source of (often severe) gastroenteritis.

In bacterium-induced diarrhoea, rapid loss of fluids and electrolytes results from inhibition of the normal absorptive function of the intestine as well as the activation of secretory processes. (Viswanathan, Hodges et al. 2009)

Differential Diagnosis

Other potential causes of signs and symptoms that mimic those seen in gastroenteritis that need to be ruled out include:


Volvulus, a bowel obstruction with a loop of bowel whose nose has abnormally twisted on itself.

Inflammatory bowel disease,

Urinary tract infections,

Diabetes mellitus: diabetic ketoacidosis

Pancreatic insufficiency,

Short bowel syndrome,

Whipple's disease,

Celiac disease,

Laxative abuse should also be considered.

There is an association between acid suppression (with proton pump inhibitors and H2 receptor antagonists) and an increased risk of enteric infection. (Leonard, Marshall et al. 2007)

Conventional Treatment

Gastroenteritis is usually an acute and self-limiting disease that does not require medication.

Oral Rehydration Therapy

The preferred treatment in those with mild to moderate dehydration is oral rehydration therapy (ORT). (Chow, Leung et al. 2010) (Hartling, Bellemare et al. 2006)


Ondansetron is a serotonin 5-HT3 receptor antagonist used mainly as an antiemetic to treat nausea and vomiting. (Carter and Fedorowicz 2012)

The use of antiemetics is a controversial topic in treatment of pediatric gastroenteritis. Although not recommended by the American Academy of Pediatrics, antiemetics are commonly prescribed by physicians. A review of the literature shows side effects of promethazine, prochlorperazine, and metoclopramide are common and potentially dangerous. Ondansetron has recently been studied as an adjunct to oral rehydration therapy in treatment of acute gastroenteritis with mild to moderate dehydration. Although studies are limited, early research suggests the medication is safe when used in a single dose and can be effective to prevent vomiting, the need for intravenous fluids, and hospital admission. (Manteuffel 2009)

Natural Therapies


The BRAT diet (bananas, rice, applesauce, toast and tea) is no longer recommended, as it contains insufficient nutrients and has no benefit over normal feeding. (King, Glass et al. 2003)

Drinks especially high in simple sugars, such as soft drinks and fruit juices, are not recommended in children under 5 years of age as they may increase diarrhea. (King, Glass et al. 2003)

Bee Honey

Bee honey added to oral rehydration therapy promoted rehydration of the body and sped recovery from vomiting and diarrhea. (Abdulrhman, Mekawy et al. 2010)

Coconut Water

Young coconut water may be helpful for home rehydration in children with mild gastroenteritis, but osmolality values showed great variation throughout maturation. (Adams and Bratt 1992)


Zinc supplementation appears to be effective in both treating and preventing diarrhea among children in the developing world. (Lazzerini and Ronfani 2012) (Salvatore, Hauser et al. 2007) (Patel, Mamtani et al. 2011) (Patel, Mamtani et al. 2010)


Probiotics have been shown to be beneficial in reducing both the duration of illness and the frequency of stools. They may also be useful in preventing and treating antibiotic associated diarrhea. (Allen, Martinez et al. 2010) (Johnston, Goldenberg et al. 2011) (Hempel, Newberry et al. 2012) (Erdogan, Tanyeri et al. 2012)

The vast majority of the published trials show a statistically significant benefit and moderate clinical benefit of a few, well-identified probiotic strains-mostly Lactobacillus GG and S. boulardii-in the treatment of acute watery diarrhea, and particularly those due to rotavirus. (Guandalini 2011)

The cost/benefit ratio of probiotics in the ambulatory treatment of acute infectious gastro-enteritis with or without a synbiotic food supplement (containing fructo-oligosaccharides and probiotic strains of Streptoccoccus thermophilus, Lactobacillus rhamnosus, Lactobacillus acidophilus, Bifidobacterium lactis and Bifidobacterium infantis) has been studied in 111 children. Although use of the synbiotic supplementation increased cost, add-on medication and extra consultations were reduced, resulting in a reduction of health care cost of 25%. (Vandenplas and De Hert 2012) (Passariello, Terrin et al. 2012) (Vandenplas and De Hert 2011)

The use of Lactobacillus GG is associated with moderate clinical benefits in the treatment of acute diarrhoea in children. (Szajewska, Skorka et al. 2007) (Piescik-Lech, Urbanska et al. 2013) (Ventola, Lehtoranta et al. 2012)


A recent study investigated the anti-viral effects of tannins on 12 different viruses including both enveloped viruses (influenza virus H3N2, H5N3, herpes simplex virus-1, vesicular stomatitis virus, Sendai virus and Newcastle disease virus) and non-enveloped viruses (poliovirus, coxsachievirus, adenovirus, rotavirus, feline calicivirus and mouse norovirus). We found that extracts from persimmon (Diospyros kaki), which contains ca. 22% of persimmon tannin, reduced viral infectivity in more than 4-log scale against all of the viruses tested, showing strong anti-viral effects against a broad range of viruses. Other tannins derived from green tea, acacia and gallnuts were effective for some of the viruses, while the coffee extracts were not effective for any of the virus. (Ueda, Kawabata et al. 2013)

Tannic acid inhibited norovirus binding to HBGA receptors. (Zhang, Dai et al. 2012) (Su and D'Souza 2012)

Grape Seed Extract

A recent study evaluated the effect of commercial GSE, Gravinol-S, on the infectivity of human enteric virus surrogates (feline calicivirus, FCV-F9; murine norovirus, MNV-1; and bacteriophage MS2) and hepatitis A virus (HAV; strain HM175). GSE caused significant reduction of the four virus titers. (Johnston, Goldenberg et al. 2011)


Cranberry juice (CJ) and cranberry proanthocyanidins (PAC) are widely known for their antibacterial, antiviral, and pharmacological activities. CJ and PAC show promise as natural antivirals that could potentially be exploited for foodborne viral illness treatment and prevention. (Su, Howell et al. 2010) (Su, Howell et al. 2010)


Human noroviruses bind with their capsid-protruding domains to histo-blood-group antigens (HBGAs), an interaction thought to direct their entry into cells. Citrate and other glycomimetics have the potential to block human noroviruses from binding to HBGAs. (Hansman, Shahzad-Ul-Hussan et al. 2012)


Plaque reduction of human enteric virus surrogates by chitosan treatment show promise for its potential application in the food environment. (Su, Zivanovic et al. 2009)


L-glutamine may be helpful in mucositis: intestinal mucosal damage of the gastrointestinal tract. (Noe 2009)


An NIH study found that adjunct therapy with butyrate enema during shigellosis led to early reduction of inflammation and enhanced LL-37 expression in the rectal epithelia with prolonged release of LL-37 in the stool. (Raqib, Sarker et al. 2012)

Butyrate exerts potent effects on a variety of colonic mucosal functions such as inhibition of inflammation and carcinogenesis, reinforcing various components of the colonic defence barrier and decreasing oxidative stress. (Hamer, Jonkers et al. 2008)

Butyrate enema therapy stimulated colonic repair, as evidenced by clinical recovery, decreased inflammation, and restoration of SCFA stimulated electrolyte absorption in experimental colitis in the rat. (Butzner, Parmar et al. 1996)


Abdulrhman, M. A., M. A. Mekawy, et al. (2010). "Bee honey added to the oral rehydration solution in treatment of gastroenteritis in infants and children." J Med Food 13(3): 605-9 PMID: 20438327

Adams, W. and D. E. Bratt (1992). "Young coconut water for home rehydration in children with mild gastroenteritis." Trop Geogr Med 44(1-2): 149-53 PMID: 1496708

Agrawal, N., U. K. Rani, et al. (2012). "Eosinophilic gastroenteritis: a diagnosis behind the curtains." J Clin Diagn Res 6(10): 1789-90 PMID: 23373056

Allen, S. J., E. G. Martinez, et al. (2010). "Probiotics for treating acute infectious diarrhoea." Cochrane Database Syst Rev(11): CD003048 PMID: 21069673

Butzner, J. D., R. Parmar, et al. (1996). "Butyrate enema therapy stimulates mucosal repair in experimental colitis in the rat." Gut 38(4): 568-73 PMID: 8707089

Carter, B. and Z. Fedorowicz (2012). "Antiemetic treatment for acute gastroenteritis in children: an updated Cochrane systematic review with meta-analysis and mixed treatment comparison in a Bayesian framework." BMJ Open 2(4) PMID: 22815462

Chow, C. M., A. K. Leung, et al. (2010). "Acute gastroenteritis: from guidelines to real life." Clin Exp Gastroenterol 3: 97-112 PMID: 21694853

Elliott, E. J. (2007). "Acute gastroenteritis in children." BMJ 334(7583): 35-40 PMID: 17204802

Erdogan, O., B. Tanyeri, et al. (2012). "The comparition of the efficacy of two different probiotics in rotavirus gastroenteritis in children." J Trop Med 2012: 787240 PMID: 22778754

Guandalini, S. (2011). "Probiotics for prevention and treatment of diarrhea." J Clin Gastroenterol 45 Suppl: S149-53 PMID: 21992955

Hamer, H. M., D. Jonkers, et al. (2008). "Review article: the role of butyrate on colonic function." Aliment Pharmacol Ther 27(2): 104-19 PMID: 17973645

Hansman, G. S., S. Shahzad-Ul-Hussan, et al. (2012). "Structural basis for norovirus inhibition and fucose mimicry by citrate." J Virol 86(1): 284-92 PMID: 22031945

Hartling, L., S. Bellemare, et al. (2006). "Oral versus intravenous rehydration for treating dehydration due to gastroenteritis in children." Cochrane Database Syst Rev(3): CD004390 PMID: 16856044

Hempel, S., S. J. Newberry, et al. (2012). "Probiotics for the prevention and treatment of antibiotic-associated diarrhea: a systematic review and meta-analysis." JAMA 307(18): 1959-69 PMID: 22570464

Johnston, B. C., J. Z. Goldenberg, et al. (2011). "Probiotics for the prevention of pediatric antibiotic-associated diarrhea." Cochrane Database Syst Rev(11): CD004827 PMID: 22071814

King, C. K., R. Glass, et al. (2003). "Managing acute gastroenteritis among children: oral rehydration, maintenance, and nutritional therapy." MMWR Recomm Rep 52(RR-16): 1-16 PMID: 14627948

Koo, H. L., N. Ajami, et al. (2010). "Noroviruses: The leading cause of gastroenteritis worldwide." Discov Med 10(50): 61-70 PMID: 20670600

Lazzerini, M. and L. Ronfani (2012). "Oral zinc for treating diarrhoea in children." Cochrane Database Syst Rev 6: CD005436 PMID: 22696352

Leonard, J., J. K. Marshall, et al. (2007). "Systematic review of the risk of enteric infection in patients taking acid suppression." Am J Gastroenterol 102(9): 2047-56; quiz 2057 PMID: 17509031

Manteuffel, J. (2009). "Use of antiemetics in children with acute gastroenteritis: Are they safe and effective?" J Emerg Trauma Shock 2(1): 3-5 PMID: 19561947

Noe, J. E. (2009). "L-glutamine use in the treatment and prevention of mucositis and cachexia: a naturopathic perspective." Integr Cancer Ther 8(4): 409-15 PMID: 19942578

Passariello, A., G. Terrin, et al. (2012). "Randomised clinical trial: efficacy of a new synbiotic formulation containing Lactobacillus paracasei B21060 plus arabinogalactan and xilooligosaccharides in children with acute diarrhoea." Aliment Pharmacol Ther 35(7): 782-8 PMID: 22324448

Patel, A., M. Mamtani, et al. (2010). "Therapeutic value of zinc supplementation in acute and persistent diarrhea: a systematic review." PLoS One 5(4): e10386 PMID: 20442848

Patel, A. B., M. Mamtani, et al. (2011). "What zinc supplementation does and does not achieve in diarrhea prevention: a systematic review and meta-analysis." BMC Infect Dis 11: 122 PMID: 21569418

Piescik-Lech, M., M. Urbanska, et al. (2013). "Lactobacillus GG (LGG) and smectite versus LGG alone for acute gastroenteritis: a double-blind, randomized controlled trial." Eur J Pediatr 172(2): 247-53 PMID: 23114849

Raqib, R., P. Sarker, et al. (2012). "Efficacy of sodium butyrate adjunct therapy in shigellosis: a randomized, double-blind, placebo-controlled clinical trial." BMC Infect Dis 12: 111 PMID: 22574737

Salvatore, S., B. Hauser, et al. (2007). "Probiotics and zinc in acute infectious gastroenteritis in children: are they effective?" Nutrition 23(6): 498-506 PMID: 17499972

Su, X. and D. H. D'Souza (2012). "Inactivation of human norovirus surrogates by benzalkonium chloride, potassium peroxymonosulfate, tannic acid, and gallic acid." Foodborne Pathog Dis 9(9): 829-34 PMID: 22897744

Su, X., A. B. Howell, et al. (2010). "Antiviral effects of cranberry juice and cranberry proanthocyanidins on foodborne viral surrogates--a time dependence study in vitro." Food Microbiol 27(8): 985-91 PMID: 20832675

Su, X., A. B. Howell, et al. (2010). "The effect of cranberry juice and cranberry proanthocyanidins on the infectivity of human enteric viral surrogates." Food Microbiol 27(4): 535-40 PMID: 20417404

Su, X., S. Zivanovic, et al. (2009). "Effect of chitosan on the infectivity of murine norovirus, feline calicivirus, and bacteriophage MS2." J Food Prot 72(12): 2623-8 PMID: 20003751

Szajewska, H., A. Skorka, et al. (2007). "Meta-analysis: Lactobacillus GG for treating acute diarrhoea in children." Aliment Pharmacol Ther 25(8): 871-81 PMID: 17402990

Ueda, K., R. Kawabata, et al. (2013). "Inactivation of Pathogenic Viruses by Plant-Derived Tannins: Strong Effects of Extracts from Persimmon (Diospyros kaki) on a Broad Range of Viruses." PLoS One 8(1): e55343 PMID: 23372851

Vandenplas, Y. and S. De Hert (2012). "Cost/benefit of synbiotics in acute infectious gastroenteritis: spend to save." Benef Microbes 3(3): 189-94 PMID: 22835702

Vandenplas, Y. and S. G. De Hert (2011). "Randomised clinical trial: the synbiotic food supplement Probiotical vs. placebo for acute gastroenteritis in children." Aliment Pharmacol Ther 34(8): 862-7 PMID: 21899583

Ventola, H., L. Lehtoranta, et al. (2012). "Effects of the viability of Lactobacillus rhamnosus GG on rotavirus infection in neonatal rats." World J Gastroenterol 18(41): 5925-31 PMID: 23139609

Viswanathan, V. K., K. Hodges, et al. (2009). "Enteric infection meets intestinal function: how bacterial pathogens cause diarrhoea." Nat Rev Microbiol 7(2): 110-9 PMID: 19116615

Zhang, X. F., Y. C. Dai, et al. (2012). "Tannic acid inhibited norovirus binding to HBGA receptors, a study of 50 Chinese medicinal herbs." Bioorg Med Chem 20(4): 1616-23 PMID: 22285570