Salmonella Infection Guide: Symptoms, Causes, Diagnosis, and Treatment
Updated: 49 minutes ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: September 2026
TL;DR
Salmonella infection (salmonellosis) is a common bacterial illness of the intestinal tract caused by eating or drinking contaminated food or water — most often raw or undercooked meat, poultry, seafood, eggs, or unpasteurized milk. Most people develop diarrhea, fever, and abdominal cramps within 8 to 72 hours of exposure, and the illness typically lasts a few days to a week. Most healthy people recover without specific treatment; the priority is replacing fluids and electrolytes. Seek care if you are an infant, older adult, or immunocompromised and the illness persists, involves high fever or bloody stools, or causes dehydration. Antibiotics are reserved for bloodstream infection, severe illness, or weakened immunity — and can actually do harm in ordinary cases.
Quick Answer
Salmonella is a common bacterial infection of the intestinal tract caught from contaminated food or water — it is not the "stomach flu." Symptoms typically start 8 to 72 hours after exposure (incubation can range from 6 hours to 6 days) and include diarrhea, stomach cramps, fever, nausea, vomiting, chills, headache, and sometimes blood in the stool. The illness lasts a few days to a week for most people, though diarrhea can last up to 10 days. Treatment is usually just fluids to prevent dehydration; antibiotics are used only for bloodstream infection, severe illness, or weakened immunity.
What Is Salmonella Infection?
Salmonella infection, also called salmonellosis, is a common bacterial disease that affects the intestinal tract. The bacteria live in the intestines of people, animals, and birds, and are shed through stool (feces). Humans become infected most frequently through contaminated water or food.
Some people with salmonella have no symptoms at all. When illness strikes, most people develop diarrhea, fever, and stomach (abdominal) cramps within 8 to 72 hours after exposure. Here is the reassuring part: most healthy people recover within a few days to a week without specific treatment.
That said, diarrhea can cause severe dehydration requiring prompt medical attention, and life-threatening complications can develop if the infection spreads beyond the intestines.
What Are the Signs and Symptoms?
Salmonella infection is usually caused by eating raw or undercooked meat, poultry, and eggs or egg products, or by drinking unpasteurized milk. The incubation period — the time between exposure and illness — can be 6 hours to 6 days. It is very common for people with salmonella to believe they have the stomach flu.
Possible sign or symptom | Notes |
Diarrhea | The most common sign; may last up to 10 days |
Stomach (abdominal) cramps | The crampy pain that usually drives the illness |
Fever | Often accompanies the diarrhea |
Nausea | Queasiness with or without vomiting |
Vomiting | Contributes to fluid loss |
Chills | Alongside the fever |
Headache | General flu-like aching |
Blood in the stool | A sign that warrants a call to your provider |
Signs and symptoms generally last a few days to a week. Diarrhea may last up to 10 days — and it may take several months before your bowels return to usual stool habits. One more detail worth knowing: a few varieties of salmonella bacteria result in typhoid fever, a sometimes deadly disease that is more common in developing countries.
When Should You See a Doctor?
Most people don't need to seek medical attention for salmonella infection because it clears up on its own within a few days.
However, if the affected person is an infant, young child, older adult, or someone with a weakened immune system, call a healthcare provider if the illness lasts more than a few days, is associated with high fever or bloody stools, or appears to be causing dehydration — signs include urinating less than usual, dark-colored urine, and a dry mouth and tongue.
How Do You Catch Salmonella?
The bacteria live in the intestines of people, animals, and birds. Most people are infected by consuming food or water that has been contaminated by feces.
Infected Food and Water
Source | How it becomes contaminated |
Raw meat, poultry and seafood | Feces may get onto raw meat and poultry during the butchering process; seafood may be contaminated if harvested from contaminated water |
Raw or undercooked eggs | Some infected chickens produce eggs containing salmonella before the shell is even formed; raw eggs appear in homemade mayonnaise and hollandaise sauce |
Unpasteurized dairy products | Unpasteurized (raw) milk and milk products may be contaminated — pasteurization kills salmonella |
Fruits and vegetables | Some fresh produce, particularly imported, may be irrigated in the field or washed during processing with contaminated water; juices from raw meat and poultry can also contaminate uncooked foods like salads in the kitchen |
Food can also become contaminated when prepared by people who don't wash their hands thoroughly after using the toilet, changing a diaper, or handling contaminated food. Infection can also occur if you touch a contaminated surface and then put your fingers in your mouth. And pets — especially birds and reptiles — can carry the bacteria on their feathers, fur, or skin, or in their feces; some pet foods may be contaminated as well.
Who Is at Higher Risk?
Risk factors fall into two groups: activities that bring you into closer contact with the bacteria, and health problems that weaken your resistance.
Risk factor | Why it raises risk |
International travel | Infection — including typhoid-causing varieties — is more common in developing countries with poor sanitation |
Owning, handling or petting animals | Birds and reptiles can carry salmonella; it is also found in animal pens, tanks, cages, and litter boxes |
Antacids | Lowering stomach acidity allows more salmonella bacteria to survive — strong stomach acid is a natural defense |
Inflammatory bowel disease | Damages the intestinal lining, making it easier for the bacteria to take hold |
Recent antibiotic use | Reduces the "good" bacteria in your intestines, impairing your ability to fight the infection |
Weakened immune system | HIV/AIDS, sickle cell disease, malaria, anti-rejection drugs after organ transplants, and corticosteroids all weaken the body's ability to fight infection |
What Are the Possible Complications?
Salmonella infection is usually not life-threatening. But in certain people — especially infants and young children, older adults, transplant recipients, pregnant women, and people with weakened immune systems — complications can be dangerous.
Complication | What it involves |
Dehydration | Warning signs: urinating less than usual or dark-colored urine, dry mouth and tongue, sunken eyes, no tears when crying, unusual tiredness, irritability or confusion |
Bacteremia | Bacteria enter the bloodstream and infect tissues throughout the body: the urinary system (urinary tract infection), the tissues around the brain and spinal cord (meningitis), the heart lining or valves (endocarditis), bones or bone marrow (osteomyelitis), or the lining of blood vessels — especially if you have had a vascular graft such as bypass surgery |
Reactive arthritis | Also known as Reiter's syndrome: eye irritation, painful urination, and painful joints |
How Is Salmonella Diagnosed?
Salmonella infection is usually diagnosed based on signs and symptoms. Two tests exist when needed.
Diagnostic step | What it does |
Stool sample test | Can detect the bacteria — but most people have recovered from their symptoms by the time results return |
Blood test | May be needed if your provider suspects the bacteria have entered your bloodstream |
How Is Salmonella Treated?
Most healthy people recover within a few days to a week without specific treatment. Preventing dehydration with adequate fluid intake can help you recover.
Treating Dehydration
Treatment focuses on replacing lost fluids and electrolytes — the minerals that balance the amount of water in your body. If dehydration is severe, emergency room care or hospitalization may be needed so that fluids can be delivered directly into a vein (intravenously).
Medications
Medication | When it helps — and when it doesn't |
Anti-diarrheals | Medications such as loperamide (Imodium A-D) can help relieve cramping from diarrhea — but they may also prolong the diarrhea associated with salmonella |
Antibiotics | Prescribed to kill the bacteria if your provider suspects bloodstream entry, your infection is severe, or you have a weakened immune system |
One important caution on antibiotics: they are not helpful in most cases of salmonella infection. In fact, antibiotics may extend the period in which you carry the bacteria and can infect others, and they can increase your risk of getting infected again (relapse).
What Self-Care Steps Help?
Even if you don't need medical attention, you need to take care not to become dehydrated — a common concern with diarrhea and vomiting.
Self-care step | What to do |
Drink more fluids (adults) | Water or other liquids; note that diarrhea may be worsened by full-strength fruit juice and soft drinks |
Use oral rehydration solutions (infants and children) | Over-the-counter solutions contain water and salts in specific proportions to replenish both fluids and electrolytes |
How Can You Prevent Salmonella?
Safe food preparation, hand-washing, and avoiding contamination keep both you and others safe — especially when cooking for or caring for infants, older adults, and people with weakened immune systems.
Prevention step | What to do |
Wash your hands (20 seconds with soap and water) | After using the toilet, changing a diaper, handling raw meat or poultry, cleaning up pet feces, and touching pets or animals and their habitats — especially reptiles or birds |
Keep things separate | Store raw meat, poultry and seafood away from other foods in your refrigerator; use two cutting boards (one for raw meat, one for fruits and vegetables); never place cooked food on an unwashed plate that previously held raw meat; wash food preparation surfaces thoroughly |
Avoid eating raw eggs | Homemade cookie dough, ice cream, mayonnaise, hollandaise sauce, and eggnog all contain raw eggs — if you must consume raw eggs, make sure they've been pasteurized |
Cook and store food properly | Cook food thoroughly and refrigerate or freeze food promptly |
How Should You Prepare for Your Appointment?
You may want to bring a family member or friend along — someone may remember information you missed or forgot. Before the appointment, find out about any pre-appointment restrictions such as diet changes, make a list of your symptoms including any that may seem unrelated, make a list of key personal information including major stresses, recent life changes, or recent travel, make a list of all medications, vitamins, herbs, or supplements you're taking with dosages, and make a list of questions to ask your provider.
Expect your provider to ask when the illness began, the frequency of vomiting or diarrhea, whether vomit or stool contains visible bile, mucus, or blood, whether you have a fever, and whether you have recently traveled outside the country. Being prepared helps you make the most of your appointment time.
Conclusion
Salmonella has one thing going for it: in most healthy people, it is self-limiting — a few days to a week, and gone. But it also has a catch most people miss: the very antibiotics that fix so many infections can prolong bacterial carriage and raise relapse risk when used for ordinary salmonella. The treatment that matters is the simplest one — fluids and electrolytes, before dehydration ever sets in. And prevention is entirely within your control: 20 seconds of handwashing, two cutting boards, pasteurized eggs and milk, and thorough cooking. If an infant, young child, older adult, or anyone immunocompromised is sick for more than a few days, has high fever or bloody stools, or shows signs of dehydration, don't wait it out — call a provider.
Frequently Asked Questions
What exactly is salmonella infection?
Salmonellosis is a common bacterial disease of the intestinal tract caused by consuming food or water contaminated by feces — the bacteria live in the intestines of people, animals, and birds.
What are the typical symptoms?
Diarrhea, stomach (abdominal) cramps, and fever, along with nausea, vomiting, chills, headache, and sometimes blood in the stool — symptoms people often mistake for the "stomach flu."
How soon after exposure do symptoms appear?
Most people develop symptoms within 8 to 72 hours of exposure, though the incubation period can range from 6 hours to 6 days.
How long does salmonella last?
Symptoms generally last a few days to a week; diarrhea may last up to 10 days, and normal bowel habits can take several months to return.
Do you always need antibiotics?
No — antibiotics are not helpful in most cases and can prolong the period you carry the bacteria and increase relapse risk. They are reserved for suspected bloodstream infection, severe illness, or a weakened immune system.
When should you see a doctor?
Call a provider for infants, young children, older adults, or immunocompromised people if the illness lasts more than a few days, involves high fever or bloody stools, or shows signs of dehydration such as urinating less, dark urine, and dry mouth and tongue.
What foods are most commonly involved?
Raw or undercooked meat, poultry, and seafood; raw or undercooked eggs (including homemade mayonnaise and sauces); unpasteurized (raw) milk; and fruits and vegetables contaminated by irrigation or processing water or kitchen cross-contamination.
Can pets give you salmonella?
Yes — animals, especially birds and reptiles, can carry the bacteria on their feathers, fur, or skin or in their feces, and it can also be found in animal pens, tanks, cages, and litter boxes; some pet foods have been contaminated too.
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This article is for general informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare professional about any medical condition or treatment decision.
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