Self-Care, Dietary Changes, OTC Medications, Antibiotics, and Other Options

By Barbara Bolen, PhD 

 Medically reviewed by Jay N. Yepuri, MD

Different types of stomach infections cause different symptoms and may need to be treated differently. These infections, called gastroenteritis or "stomach flu," can be caused by bacteria, viruses, or parasites that are passed through contaminated food or water or by sharing personal care items.

Mild stomach infections usually resolve on their own and only require self-care to help ease symptoms. In rare cases, antibiotics may be prescribed to treat severe bacterial gastroenteritis.

This article describes the symptoms and causes of different types of stomach infections. It also explains how each is treated and when it is time to see a healthcare provider.

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Viral Stomach Infections

Viruses are the most common cause of gastroenteritis and what most refer to when talking about "stomach flu." Several types can cause stomach infections, the most common of which include:1

  • Rotaviruses

  • Noroviruses

  • Adenoviruses

Noroviruses are more common in adults, while adenoviruses and rotaviruses are more common in infants and young children

Does COVID Cause Stomach Flu?

COVID-19 can cause stomach flu symptoms like diarrhea, nausea, stomach pain, and vomiting, either on their own or alongside respiratory symptoms like shortness of breath.1

Symptoms

Symptoms of viral gastroenteritis can vary based on the severity of the infection and may include:1

  • Watery diarrhea

  • Nausea

  • Vomiting

  • Headache

  • Fever

  • Abdominal cramps

  • Chills

  • Clammy skin

  • Sweating

  • Joint stiffness

  • Muscle pain   

Symptoms tend to develop suddenly, usually within four to 48 hours of exposure to the virus. For most people, the symptoms go away after a few days without treatment.1

Causes

Viral gastroenteritis is typically a foodborne illness, caused by eating contaminated food or sharing utensils or glassware with someone who is infected. It can also be passed from person to person through close physical contact.2

The route of infection is the fecal-oral route, meaning that stool from someone with the virus gets onto food or objects that enter the mouth. Unsanitary kitchens can increase the risk. Not washing your hands after using the toilet can do the same.3

Bacterial Stomach Infections

Bacterial stomach infections are the second most common cause of gastroenteritis, most often referred to as "food poisoning." They can be caused by many different types of bacteria such as:4

  • Campylobacter

  • Clostridium difficile

  • Escherichia coli (E. coli)

  • Salmonella

  • Shigella

  • Staphylococcus aureus

Symptoms

Symptoms of bacterial gastroenteritis are largely the same as viral gastroenteritis but tend to be more severe. Acute symptoms that for more than three days or cause dehydration are most likely due to bacteria. Bloody diarrhea is also a common sign of bacterial gastroenteritis.5

Symptoms tend to start within 12 hours of eating contaminated food and can last up to seven days in severe cases.5

Causes

Bacterial gastroenteritis typically occurs when food contaminated with feces (stool) remains at room temperature for several hours, allowing the transmitted bacteria to multiply to toxic levels.

The foods most associated with food poisoning include:4

  • Raw or undercooked meat

  • Poultry

  • Seafood

  • Eggs

  • Raw sprouts

  • Unpasteurized milk

As with viral gastroenteritis, the fecal-oral route is the source of transmission. Some transmissions occur from human to human, such as when unwashed hands touch food or when engaging in oral-anal sex (a.k.a. "rimming"). Other transmissions occur when farm produce is contaminated with animal manure.5

Parasitic Stomach Infections

Parasites are less common causes of stomach infections but they can cause severe gastrointestinal symptoms. They are especially common in the developing world where access to clean water is often limited.6

Parasitic stomach infections are caused by two classes of parasites: intestinal worms (also known as helminths) and one-celled creatures called protozoa. The most common include:6

  • Giardia

  • Cystoisospora belli

  • Tapeworms

Symptoms

Parasitic stomach infections tend to take longer to develop than viral or bacterial gastroenteritis, causing symptoms within seven to 14 days of exposure.6

Symptoms include:6

  • Diarrhea

  • Gas

  • Foul-smelling stools

  • Greasy, floating stools

  • Abdominal cramps

  • Nausea or vomiting

  • Fatigue

  • Fever

  • Itchy skin

Symptoms also take longer to resolve, often between two and six weeks. Severe cases can lead to reactive arthritis, causing the swelling and stiffness of joints.6

Causes

Parasitic stomach infections are often passed through contaminated water. Travel to developing countries and drinking public water after a natural disaster are common scenarios for these infections.

Parasitic gastroenteritis can also be spread through the fecal-oral route among small children in daycare centers and through sexual practices like "rimming" (anal-oral sex) among men who have sex with men (MSM).6

Treatments

Gastroenteritis is usually a self-limiting disease that does not require medication. The treatment is largely the same whether the cause is viral, bacterial, or parasitic. The primary aim is to manage the acute symptoms and prevent dehydration.

Self-Care

If you start to develop the signs of gastroenteritis, stop eating solid foods for at least a few hours to avoid excessive vomiting. You can chew on a sliver of fresh ginger, sip ginger tea or a flat ginger ale, or suck on a ginger candy to help stem nausea symptoms.

Getting plenty of sleep is also important when dealing with a stomach infection. Studies have shown that quality sleep can support the immune system and shorten recovery times from stomach flu.7

Let Yourself Vomit

Vomiting is the body's way of purging toxins or foreign invaders from the digestive tract. As unpleasant as it may seem, if you have the urge to vomit, don't try to stop it.

However, vomiting can lead to the excess loss of fluids, so it is important to replenish those fluids as much as you can to avoid dehydration.

Stay Hydrated

When you have a stomach infection, the excess loss of fluids through vomiting and/or diarrhea can cause dehydration. Unless you make an effort to replenish those fluids, you could end up in hospital with symptoms ranging from dizziness and fainting to kidney failure and shock.

Arguably, the best option for rehydration is plain water, but you may need an oral rehydration solution if vomiting and diarrhea are severe and you've lost a lot of electrolytes.1

If you can't keep fluids down, try taking tiny sips or sucking on ice chips or a popsicle. Doing so may also help ease nausea.

OTC Medications

Sometimes, over-the-counter (OTC) medications may be needed to ease gastroenteritis symptoms like diarrhea, nausea, and body aches.

Options include:

  • Anti-diarrheals: Imodium A-D (loperamide) is an OTC drug that is effective at stopping diarrhea. Bismuth-containing remedies like Pepto-Bismol and Kaopectate can also help, while gently coating the stomach to ease nausea symptoms.

  • Analgesics: Pain relievers like Tylenol (acetaminophen) are good at easing body aches, pains, and fever. Unlike nonsteroidal anti-inflammatory drugs (NSAIDs) like Advil (ibuprofen), Tylenol is also far safer for the stomach.

Antibiotics and Other Antimicrobials

Most stomach infections do not need prescription medications. However, if the infection is particularly severe and causes massive diarrhea or bloody stools, your healthcare provider may prescribe certain antimicrobial drugs to help clear the infection.

These may include:

  • Antibiotics: Drugs like Zithromax (azithromycin), Cipro (ciprofloxacin), and tetracycline are used to treat bacterial infections.8

  • Antiparasitic drugs: This involves a wide range of agents that help kill intestinal parasites in different ways. Options include metronidazole, praziquantel, and albendazole.9

  • Antivirals: These are rarely used to treat viral gastroenteritis. The one exception may be with COVID-19 in which antivirals like Paxlovid (nirmatrelvir/ritonavir) and Lagevrio (molnupiravir) are commonly prescribed to people at high risk of COVID complications.

Do I Need Antibiotics?

Antibiotics are only used when bacterial gastroenteritis is causing extremely high fever, severe diarrhea, or other severe symptoms. They may also be prescribed to people with a compromised immune system who are at risk of serious complications.8

Change Your Diet

As symptoms begin to ease and your stomach starts to settle, try eating bland foods that are easy to digest and help bind loose stools.

Good foods to eat include:

  • Soda crackers

  • Rice

  • Gelatin

  • Unbuttered toast

  • Potatoes

  • Bananas

Avoid foods that promote nausea or diarrhea, such as:

  • Dairy products

  • Fatty foods

  • Sugary foods

  • Spicy foods

  • Alcohol

  • Caffeine

When to See a Healthcare Provider

Severe stomach infections should never be ignored, particularly if symptoms persist or are getting worse.

See your healthcare provider right away if you have:3

  • Symptoms of dehydration, such as dry mouth, dark-colored urine, infrequent urination, or lightheadedness

  • A fever over 100.4 F for more than a few days

  • Diarrhea or vomiting for more than two days

  • Tarry or bloody stools

  • Heart palpitations or you faint

Summary

Stomach infections, also known as gastroenteritis, may be caused by bacteria, viruses, or parasites. Symptoms include diarrhea, stomach pain, nausea or vomiting, fever, and fatigue. Most cases are not treated with antibiotics or any other antimicrobial agents. Treatment is mainly focused on easing symptoms and ensuring that you remain well-hydrated.

Sources

MedlinePlus. Viral gastroenteritis.

National Institute of Diabetes and Digestive and Kidney Diseases. Definition & facts for viral gastroenteritis (“stomach flu”).

National Institute of Diabetes and Digestive and Kidney Diseases. Symptoms & causes of viral gastroenteritis ("stomach flu").

MedlinePlus. Bacterial gastroenteritis.

Bintsis T. Foodborne pathogens. AIMS Microbiol. 2017;3(3):529–563. doi:10.3934/microbiol.2017.3.529

Zhang T, Liu D, Tian D, Xia L. The roles of nausea and vomiting in COVID-19: did we miss something? Journal of Microbiology, Immunology and Infection. 2021;54(4):541-546.

Besedovsky L, Lange T, Haack M. The sleep-immune crosstalk in health and disease. Physiol Rev. 2019;99(3):1325-1380. doi: 10.1152/physrev.00010.2018.

Malik OAA. Role of antimicrobials in the treatment of adult patients presenting to the emergency department with acute gastroenteritis - A mini review. Pak J Med Sci. 2017;33(2):488-492. doi:10.12669/pjms.332.11851

National Center for Biotechnology Information. Antiparasitic drugs.

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By Barbara Bolen, PhD
Barbara Bolen, PhD, is a licensed clinical psychologist and health coach. She has written multiple books focused on living with irritable bowel syndrome.