is diarrhea a symptom of covid

Can you calm COVID diarrhea & stomach troubles with probiotics?

Content reviewed by Donna Gates
Written by Body Ecology on February 8th, 2021

It’s the respiratory symptoms of COVID-19 that have gotten the most attention this past year, but many of those infected with SARS-CoV2 also report gastrointestinal woes, including diarrhea, vomiting, nausea, loss of appetite, abdominal pain, and gastrointestinal bleeding.1

What’s more, some reports suggest that GI symptoms of COVID-19 correlate with more severe respiratory symptoms and worse outcomes.2 No wonder, then, that there’s been quite a bit of buzz recently about the use of probiotics to remedy or prevent COVID-related diarrhea.

Diarrhea and COVID-19: How common is this symptom?

Your best defense against COVID is your own immune system. Taking probiotics may make the immune-supporting and diarrhea-relieving mineral zinc more bioavailable.

How typical are gastrointestinal symptoms of COVID-19? Reports vary. This isn’t surprising, given that researchers often focus on respiratory symptoms and may use different methods to classify symptoms like diarrhea.

One study in China found that COVID-19 infection led to reduced numbers of Bifidobacterium spp. and Lactobacillus spp.

Overall, studies report an incidence rate of 2 to 50 percent for diarrhea in people with COVID-19.

Whereas, in a pooled analysis of dozens of studies, researchers reported an overall diarrhea rate of 10.4 percent in patients with COVID-19. Meaning, more than one in 10 people with the disease experienced diarrhea.3

The same study also found that:

  • The virus remained present in stool for far longer than was detected with respiratory swabs, suggesting that people may remain infectious even after they get a negative nasal swab test.
  • And, interestingly, some people experience diarrhea before other symptoms of infection or as their only symptom.

As we all became armchair epidemiologists and immunologists in 2020, knowledge of ACE2 receptors ballooned. These receptors (angiotensin-converting enzyme 2 receptors) are the primary way in which SARS-CoV2 infects cells.

They do this using the serine protease TMPRSS2 for S protein priming. And, both ACE2 and TMPRSS2 are expressed in the lungs, as well as in the liver, colon, small intestinal epithelia, and the upper esophagus.

Put simply, the gastrointestinal tract is ripe for infection with the virus that causes COVID-19. But why does this lead to diarrhea and other GI symptoms?

The specific mechanisms by which SARS-CoV2 causes GI upset, including diarrhea, are not entirely known. However, it seems that the virus can affect the permeability of the intestines.

And by monopolizing ACE2 receptors, it might also affect the absorption of amino acids (the building blocks for protein) and levels of antimicrobial peptides, while upsetting the gut microbiome.4,5 One study in China found that COVID-19 infection led to reduced numbers of Bifidobacterium spp. and Lactobacillus spp.6

Another study found that:7

  • COVID-19 caused severe hypoxemia in some patients, with changes to the gut microbiome in the balance of gut microorganisms.
  • Significant reductions in probiotic species, including Bifidobacterium spp., Lactobacillus spp., and Eubacterium spp., led to significant increases in the number of pathogens, such as Corynebacterium spp., Actinobacteria spp., and Ruthenibacterium spp.

(In addition to affecting the microbiome of the gut, COVID-19 may also affect the lung microbiome; this is something that’s only just beginning to be understood by clinicians.8)

Of course, we should also note that some of the drugs used to try to treat COVID-19, such as antivirals and antibiotics, can also upset the microbiome and contribute to diarrhea and other GI symptoms.9,10 All of this strongly suggests that probiotics have a role to play in the prevention and treatment of COVID-19 symptoms and any GI issues that arise as a result of conventional treatments.

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How probiotics help restore the gut microbiome in COVID cases

While probiotics haven’t been top of mind for frontline healthcare workers battling COVID-19, some clinicians have begun to routinely treat COVID-19 patients with probiotics to preserve and replenish intestinal balance and stave off secondary infections.

Specifically, China’s National Health Commission recommended such use of probiotics as far back as February 2020, just as news of the virus (and the virus itself) was spreading worldwide.11

In a study carried out in Zhejiang province, China, patients with relatively mild symptoms of COVID-19 were more likely to have received probiotics alongside other treatments, such as interferon-alpha inhalation, lopinavir, ritonavir, and arbidol.6

In addition to the use of probiotics and zinc, antiviral drugs and monoclonal antibodies have also been seen to rapidly improve symptoms of diarrhea in people with COVID-19.12,13

Some of the most important probiotics in the fight against COVID-19 appear to include:14

  • L. casei
  • L. gasseri
  • B. longum
  • B. bifidum
  • L. rhamnosus
  • L. plantarum
  • Bbreve
  • Pediococcus pentosaceus
  • Leuconostoc mesenteroides

You may not have heard much about these last two microbes, but Pediococci are found along with other lactic acid bacteria in fermented vegetables. They don’t grow well in milk but can be found there where they inhabit Listeria. They can play a significant role in the maturation of cheese and can replace S. thermophils in cheese-making.

Leuconostoc mesenteroides bacteria initiate the fermentation process a few hours after the shredded vegetables are put into their jars or crocks. Then, as the environment becomes more acidic, they gradually die off. However, they release enzymes that continue to be active in the fermentation process.

By the time they disappear, Lactobacillus plantarum and Lactobacillus brevis have become very active and increase the acidity even more. Finally, two more Lactobacilli — sake and curvatus — enter and complete the fermentation. The fermentation of vegetables is a fascinating process and has the “Wisdom of Nature” that’s helped protect mankind for thousands of years.

Before we wrap up, a quick note on how probiotics might indirectly help with diarrhea associated with viral infection, such as with COVID-19:

  • This kind of infection is known to deplete levels of zinc, an important nutrient for immune function (among other things).15
  • Zinc deficiency also increases vulnerability to respiratory diseases and diarrhea.16
  • Fortunately, zinc supplementation can help treat acute diarrhea due to viral infection, and certain probiotic strains have been seen to enhance the bioavailability of supplemental zinc.17

In one study, Lb fermentum SR4 and Lb rhamnosus GG (LGG) increased bioavailability of zinc by up to 57 and 48 percent, respectively, when compared to zinc sulphate and zinc gluconate forms.18 Another study found that taking up to 50 mg of zinc per day suppressed SARS-CoV2 viral replication by improving patients’ own immune defenses.19

So, if you’re building your natural medicine cabinet against COVID-19, or are already dealing with diarrhea and other GI symptoms of the virus, you might want to put probiotics and zinc at the top of your list.


  1. 1. Olaimat, A.N., Aolymat, I., Al-Holy, M. et al. The potential application of probiotics and prebiotics for the prevention and treatment of COVID-19. npj Sci Food 4, 17 (2020). https://doi.org/10.1038/s41538-020-00078-9.
  2. 2. Wan Y, Li J, Shen L, et al. Enteric involvement in hospitalised patients with COVID-19 outside Wuhan. Lancet Gastroenterol Hepatol. 2020;5(6):534-535. doi:10.1016/S2468-1253(20)30118-7.
  3. 3. D’Amico F, Baumgart DC, Danese S, Peyrin-Biroulet L. Diarrhea During COVID-19 Infection: Pathogenesis, Epidemiology, Prevention, and Management. Clin Gastroenterol Hepatol. 2020;18(8):1663-1672. doi:10.1016/j.cgh.2020.04.001.
  4. 4. Gu J, Han B, Wang J. COVID-19: Gastrointestinal Manifestations and Potential Fecal-Oral Transmission. Gastroenterology. 2020 May;158(6):1518-1519. doi: 10.1053/j.gastro.2020.02.054. Epub 2020 Mar 3. PMID: 32142785; PMCID: PMC7130192.
  5. 5. Hashimoto T, Perlot T, Rehman A, et al. ACE2 links amino acid malnutrition to microbial ecology and intestinal inflammation. Nature. 2012;487(7408):477-481. Published 2012 Jul 25. doi:10.1038/nature11228.
  6. 6. Xu K, Cai H, Shen Y, Ni Q, Chen Y, Hu S, Li J, Wang H, Yu L, Huang H, Qiu Y, Wei G, Fang Q, Zhou J, Sheng J, Liang T, Li L. [Management of COVID-19: the Zhejiang experience]. Zhejiang Da Xue Xue Bao Yi Xue Ban. 2020 May 25;49(2):147-157. Chinese. doi: 10.3785/j.issn.1008-9292.2020.02.02. PMID: 32391658.
  7. 7. Yu, L., Tong, Y., Shen, G., Fu, A., Lai, Y., Zhou, X., Yuan, Y., Wang, Y., Pan, Y., Yu, Z., Li, Y., Liu, T., & Jiang, H. (2020). Immunodepletion with Hypoxemia: A Potential High Risk Subtype of Coronavirus Disease 2019. medRxiv.
  8. 8. Olaimat, A.N., Aolymat, I., Al-Holy, M. et al. The potential application of probiotics and prebiotics for the prevention and treatment of COVID-19. npj Sci Food 4, 17 (2020). https://doi.org/10.1038/s41538-020-00078-9.
  9. 9. Logan C, Beadsworth MB, Beeching NJ. HIV and diarrhoea: what is new? Curr Opin Infect Dis. 2016 Oct;29(5):486-94. doi: 10.1097/QCO.0000000000000305. PMID: 27472290.
  10. 10. Bartlett JG. Clinical practice. Antibiotic-associated diarrhea. N Engl J Med. 2002 Jan 31;346(5):334-9. doi: 10.1056/NEJMcp011603. PMID: 11821511.
  11. 11. Gao QY, Chen YX, Fang JY. 2019 Novel coronavirus infection and gastrointestinal tract. J Dig Dis. 2020;21(3):125-126. doi:10.1111/1751-2980.12851.
  12. 12. Song Y, Liu P, Shi XL, Chu YL, Zhang J, Xia J, Gao XZ, Qu T, Wang MY. SARS-CoV-2 induced diarrhoea as onset symptom in patient with COVID-19. Gut. 2020 Jun;69(6):1143-1144. doi: 10.1136/gutjnl-2020-320891. Epub 2020 Mar 5. PMID: 32139552.
  13. 13. Tian X, Li C, Huang A, et al. Potent binding of 2019 novel coronavirus spike protein by a SARS coronavirus-specific human monoclonal antibody. Emerg Microbes Infect. 2020;9(1):382-385. Published 2020 Feb 17. doi:10.1080/22221751.2020.1729069.
  14. 14. Khaled JMA. Probiotics, prebiotics, and COVID-19 infection: A review article. Saudi J Biol Sci. 2021;28(1):865-869. doi:10.1016/j.sjbs.2020.11.025.
  15. 15. Bhatnagar S, Natchu UC. Zinc in child health and disease. Indian J Pediatr. 2004 Nov;71(11):991-5. doi: 10.1007/BF02828114. PMID: 15572819.
  16. 16. Aggarwal R, Sentz J, Miller MA. Role of zinc administration in prevention of childhood diarrhea and respiratory illnesses: a meta-analysis. Pediatrics. 2007 Jun;119(6):1120-30. doi: 10.1542/peds.2006-3481. PMID: 17545379.
  17. 17. Lazzerini M. Oral zinc provision in acute diarrhea. Curr Opin Clin Nutr Metab Care. 2016 May;19(3):239-43. doi: 10.1097/MCO.0000000000000276. PMID: 26963581.
  18. 18. Lule VK, Tomar SK, Chawla P, Pophaly S, Kapila S, Arora S. Bioavailability assessment of zinc enriched lactobacillus biomass in a human colon carcinoma cell line (Caco-2). Food Chem. 2020 Mar 30;309:125583. doi: 10.1016/j.foodchem.2019.125583. Epub 2019 Oct 16. PMID: 31699555.
  19. 19. Razzaque MS. COVID-19 Pandemic: Can Maintaining Optimal Zinc Balance Enhance Host Resistance? Tohoku J Exp Med. 2020 Jul;251(3):175-181. doi: 10.1620/tjem.251.175. PMID: 32641644.


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