Bacterial Gastroenteritis: Causes, Symptoms, and Treatment
Medically reviewed by Achuta Uppu, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor treats Bacterial Gastroenteritis?
A primary care doctor treats most bacterial gastroenteritis. A gastroenterologist, a digestive doctor, may see you if it is severe. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What is Bacterial Gastroenteritis?
Bacterial gastroenteritis is a bacterial infection of the stomach or intestines. It is also called infectious diarrhea. Many bacteria can cause it. They include Campylobacter jejuni, E. coli, Salmonella, Shigella, Staphylococcus aureus, and Yersinia. One strain of E. coli, O157:H7, can cause a severe case. It often spreads through food or water.
Symptoms
Symptoms depend on the type of bacteria that caused the sickness. All types of bacterial gastroenteritis cause diarrhea. Other symptoms include:
- Abdominal cramps and abdominal pain.
- Bloody stools, or diarrhea that lasts more than 3 days.
- Loss of appetite.
- Nausea and vomiting.
- Fever.
- Feeling the need to pass stool even when the bowels are empty.
Timing differs by germ. E. coli symptoms usually start 24 to 72 hours after infection. Shigella symptoms usually start 1 to 2 days after contact. They often last 5 to 7 days.
Causes and who gets it
Bacteria reach the gut through food, water, or hands. Meat or poultry can touch bacteria during processing. Water used to grow or ship food may hold animal or human waste. Food may be handled unsafely. Raw shellfish, undercooked meats or eggs, unwashed produce, untreated water, and food left out too long can all carry germs. Young children may be at extra risk of getting dehydrated. People with weak immune systems, such as from HIV or chemotherapy, can stay sick longer.
How doctors diagnose it
The doctor checks for stomach tenderness and signs of dehydration, which means too little water in the body. Lab tests may be done on the food or a stool sample to find the germ. A stool culture is a lab test that grows bacteria from a sample. Other tests look for white blood cells in the stool, a sign of inflammation. These tests do not always show the cause of the diarrhea.
Treatment
Most people recover in a few days without treatment. The goal is to feel better and avoid dehydration. Drink enough fluids. Oral rehydration mixtures replace fluids and minerals lost through vomiting and diarrhea. The powder can be bought at a pharmacy and mixed with safe water. Get plenty of rest. If you cannot keep fluids down, you may need fluids through a vein (IV). Antibiotics are not given very often for the most common types. They may be needed if diarrhea is very severe or your immune system is weak. Drugstore medicines that slow diarrhea can help. But do not use them without asking your doctor if you have bloody diarrhea, severe diarrhea, or a fever. Never give them to children.
When to see a doctor
Contact your doctor if you see blood or pus in your stools, or your stool is black. Call if diarrhea comes with a fever above 101 degrees F (100.4 degrees F in children). Call if stomach pain does not go away after a bowel movement. Signs of dehydration, such as thirst, dizziness, or lightheadedness, also need a call. So does diarrhea after foreign travel. Call the doctor if diarrhea does not get better in 2 days for an infant or child, or 5 days for adults. Rare but serious problems include severe anemia, bleeding in the gut, and kidney failure from certain E. coli types. Shigella can also cause a rare kidney problem called hemolytic-uremic syndrome. You may need to go to the emergency room for fluids through a vein if you cannot keep fluids down. Contact your doctor for signs of a rare but severe E. coli infection: easy bruising, pale skin, or bloody urine. Call 911 right away for fainting or loss of consciousness, confusion or trouble waking up, trouble breathing, vomiting blood, severe belly pain, or sudden weakness or trouble speaking.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. Either can guide your recovery at home, check for dehydration, order stool tests when needed, and refer you to a gastroenterologist if the illness is severe.
Common questions
How long does bacterial gastroenteritis last?
Most people get better in a few days without treatment. With Shigella, symptoms usually last 5 to 7 days. Some people have symptoms for 4 or more weeks. It can take several months for bowel habits to fully return to normal.
Is bacterial gastroenteritis the same as food poisoning?
Not exactly. They overlap. Bacterial gastroenteritis is a bacterial infection of the stomach or intestines. When it comes from food, it is commonly called food poisoning. But some germs, such as E. coli, can also spread from person to person, not only through food.
Can bacterial gastroenteritis spread from person to person?
Yes, sometimes. Although it is not common, E. coli can spread from one person to another. This can happen when someone does not wash their hands after a bowel movement and then touches objects or other people's hands.
Do I need antibiotics?
Usually not. Antibiotics are not given very often for the most common types. They may be needed if diarrhea is very severe or your immune system is weak. Your doctor will decide.
Sources
- MedlinePlus - Bacterial gastroenteritis: MedlinePlus Medical Encyclopedia
- MedlinePlus - E coli enteritis: MedlinePlus Medical Encyclopedia
- Centers for Disease Control and Prevention - Signs and Symptoms of Shigella Infection
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
