What happens if you eat a bad potato?

Eating a bad potato can cause a variety of unpleasant symptoms and potentially serious health issues. Here are some quick answers to common questions about the consequences of consuming spoiled potatoes:

What are the symptoms of eating a bad potato?

Some common symptoms of eating a rotten or moldy potato include:

  • Nausea
  • Vomiting
  • Diarrhea
  • Stomach cramps
  • Headache
  • Fever

The symptoms usually start within a few hours of ingestion and tend to be relatively mild in healthy adults. More severe cases can lead to dehydration, especially in vulnerable groups like the elderly, infants, and those with compromised immune systems.

What causes these symptoms?

A potato that has gone bad is likely to contain increased levels of dangerous bacteria like E. coli, Salmonella, and Staphylococcus aureus. Consuming these bacteria can lead to food poisoning, resulting in the common symptoms of vomiting, diarrhea, and abdominal pain.

In addition, rotten potatoes may contain high levels of solanine, a natural toxin found in potatoes. Solanine poisoning can occur when potatoes turn green or sprout, both signs they are past their prime. Solanine can irritate the gastrointestinal tract, causing nausea, diarrhea, and digestive issues.

How long do the symptoms last?

For most healthy adults, the symptoms of eating a bad potato will go away on their own within 24-48 hours. Staying hydrated and getting rest can help the body recover more quickly.

In severe cases, symptoms can last 3-5 days or longer. If you experience persistent vomiting, bloody stool, high fever, or extreme pain, you should seek medical attention, as these can be signs of a more serious condition.

Can it be fatal?

While eating a spoiled potato is unlikely to be fatal in otherwise healthy people, some high-risk groups can develop life-threatening complications. Infants, young children, older adults, pregnant women, and those with compromised immune systems are most susceptible.

Bacteria like E. coli and Salmonella can occasionally lead to severe dehydration, sepsis, or kidney failure. Very high doses of solanine from extremely rotten potatoes could potentially be fatal, although human deaths are very rare.

Seeking prompt medical treatment is crucial if any dangerous symptoms develop after consuming bad potatoes.

How can you avoid getting sick?

Here are some tips for avoiding illness from bad potatoes:

  • Examine potatoes before cooking and discard any with mold, sprouts, green coloration, or foul odors.
  • Store potatoes in a cool, dry, dark place to prevent sprouting and decay.
  • Cook potatoes thoroughly to kill any bacteria present.
  • Don’t eat potato skins if the potato tastes bitter, as this can indicate solanine buildup.
  • Refrigerate cooked potatoes within 2 hours and reheat thoroughly before eating again.
  • Peel and discard any green portions of potatoes before cooking.

When should you see a doctor?

You should seek medical care if you experience:

  • Blood in vomit or stools
  • Inability to keep down fluids due to vomiting/diarrhea
  • Persistent diarrhea for more than 3 days
  • High fever (over 101°F)
  • Signs of dehydration like dizziness, weakness, or low urine output
  • Neurological symptoms like confusion, blurred vision, or seizures
  • Severe abdominal pain or swelling

Seeking prompt treatment can help prevent serious complications and help identify if anything other than food poisoning is causing your symptoms.

Who is most at risk for severe illness?

Those most likely to become severely ill from eating spoiled potatoes include:

  • Infants and young children
  • Older adults
  • Pregnant women
  • People with weakened immune systems or chronic illnesses
  • Patients taking antibiotics or acid reducers
  • People with inflammatory bowel diseases like Crohn’s or ulcerative colitis

These groups are more vulnerable to dehydration, malnutrition, or secondary infections and should take extra care to avoid consuming bad potatoes.

Can you eat potatoes that have sprouted?

It’s not recommended. Potatoes that have sprouted have higher levels of solanine, a toxin that can cause nausea, headache, cramps and diarrhea when consumed. Sprouting also indicates the potatoes are old and at higher risk for bacterial contamination.

If sprouted potatoes must be eaten, trim the sprouts off, peel the potato well and cook thoroughly. Avoid eating the peels. However, it’s safest not to eat sprouted potatoes, especially for at-risk groups.

What foodborne illnesses can bad potatoes cause?

The main foodborne illnesses that can result from eating rotten or moldy potatoes include:

  • Salmonella – Causes diarrhea, fever, abdominal cramps, and sometimes vomiting. Can take 12-72 hours for symptoms to appear.
  • E. coli – Causes severe stomach cramps, bloody diarrhea, and vomiting. Takes 3-4 days for symptoms to start.
  • Listeria – Causes fever, muscle aches, nausea. Takes 1-4 weeks for symptoms to show.
  • Staphylococcus aureus – Causes nausea, vomiting, stomach cramps. Symptoms appear within 1-6 hours.

Rarely, very high solanine levels in rotten potatoes could cause symptoms like headaches, diarrhea and gastrointestinal distress as well.

Can a bad potato make other people sick?

Yes, bad potatoes can harbor dangerous bacteria that can be passed from person to person. If one person gets sick from eating spoiled potatoes, improper food handling could lead to others consuming the same bacteria and developing illness as well.

To prevent spreading foodborne illness after exposure to bad potatoes:

  • Wash hands thoroughly with soap and water after handling
  • Disinfect any surfaces the potatoes touched
  • Don’t prepare food for others while sick
  • Avoid sharing personal items like towels, dishes, etc.

Proper cooking temperatures will kill most bacteria present, but it’s still possible for it to spread through cross-contamination of food prep areas or poor hygiene.

Can animals get sick from eating bad potatoes?

Yes, animals can also develop foodborne illness from eating rotting or moldy potatoes. Dogs and cats that ingest spoiled potatoes may vomit, have diarrhea or seem lethargic.

Livestock like cows, pigs and chickens fed moldy potatoes could become ill as well, putting food supplies at risk. Farmers must inspect potato stockpiles regularly and remove any rotting ones to protect animal health.

While not common, solanine poisoning is also possible in animals, causing neurological symptoms like weakness, confusion and difficulty breathing. Veterinary care should be sought if an animal seems ill after eating potatoes.

How can you tell if a raw potato has gone bad?

Signs a raw potato has spoiled include:

  • Greenish, grey or black discoloration
  • Wrinkled, shrivelled or softened texture
  • Moldy spots
  • Sprouting or sprout nubs
  • An unpleasant, bitter smell

Potatoes that are very old may be rubbery yet still look normal. If in doubt, it’s best to discard potatoes past their prime.

Can you eat a potato that smells a little off?

No, it’s not recommended to eat a potato with any kind of unpleasant or “off” odor, even if just slight. Foul smells indicate the potato is decaying and harbors higher levels of harmful bacteria that can cause illness.

An odd smell means chemical changes are taking place as the potato spoils. While cooking may reduce bacteria somewhat, the toxins produced by decay cannot be eliminated. When in doubt, throw it out to be safe.

Do green potatoes smell different when cut?

Yes, potatoes that have turned partly green can give off a distinct bitter, unpleasant smell when cut open. This occurs as higher solanine levels build up right under the skin.

The green color comes from sun exposure, which triggers excess chlorophyll production. At the same time, glycoalkaloids like solanine increase as part of the plant’s defense mechanisms.

The bitter smell serves as a warning not to eat green potatoes. Peeling away all green portions or discarding the whole potato is recommended.

Can you eat potatoes that have sprouted a little bit?

It’s not recommended. Even small sprouts on a potato indicate it’s past its prime and starting to decay. Sprouting causes solanine levels to rise, making the potatoes potentially toxic if eaten in large quantities.

If sprouting is minimal, trim off all sprouts, peel the potato well and cook thoroughly. But potatoes with extensive sprouting should be discarded, especially for high risk groups like children and pregnant women.

Is it OK to cut off mold and eat the rest of a potato?

No, potatoes with any mold spots should be discarded entirely. The toxins produced by mold can spread unseen throughout the potato, so cutting away visible mold does not make the rest safe to eat.

In addition, mold on a potato means it is decaying and likely harbors harmful bacteria. Even if mold isn’t visible, bacteria can still be present and lead to foodborne illness.

Can you recover an old sprouted potato?

There’s no reliable way to reverse a potato that has already sprouted and begun decaying. Trimming sprouts can slow further deterioration, but the potato should be used immediately.

Peeling and cooking thoroughly may reduce risks somewhat, but sprouted potatoes have higher solanine levels and bacterial contamination that cannot be reversed.

For food safety, it’s best to discard sprouted potatoes. Freezing or dehydrating might make them usable for crafts, but they are not recommended for consumption.

Is it dangerous to eat potatoes with a little mold?

Yes, eating potatoes with even a small amount of mold can make you sick. Mold indicates fungal growth and decay, which allows production of dangerous mycotoxins.

Mold also raises the risk of bacterial contamination. Even if you cut away visible mold, toxicity and bacteria can still be present in the rest of the potato.

Potatoes are porous, so fungi and toxins permeate deep into the flesh. Peeling or cooking doesn’t make them safe to eat once mold is present.

Can you eat a rotten potato if you cook it thoroughly?

No, it is not considered safe to eat a potato that has become rotten, even if cooked at high temperatures. The toxins and bacteria associated with rotten potatoes cannot be reversed by cooking.

While cooking can kill some bacteria, it does not eliminate the natural toxins or spores produced as the potato decays. Consuming rotten potatoes can therefore still result in foodborne illness.

What is the worst that can happen from eating bad potatoes?

For otherwise healthy adults, the most common symptoms are stomach pain, nausea, vomiting and diarrhea that resolve without treatment after 24-48 hours. Severe dehydration requiring hospitalization can occur if the vomiting and diarrhea are extreme.

In rare cases, bad potatoes could cause more serious conditions like reactive arthritis, kidney problems or sepsis. People with chronic diseases are at increased risk of complications.

Infants and people with compromised immune systems have the highest chance of life-threatening effects. They are more vulnerable to harmful bacteria that can lead to severe dehydration, malnutrition or dangerous secondary infections.


Eating spoiled, moldy, or rotten potatoes can cause unpleasant symptoms ranging from nausea and stomach cramps to vomiting and diarrhea due to bacteria and toxin exposure. While rare, severe illness requiring hospitalization is possible, especially in high risk groups.

Examine potatoes carefully before use and discard any that show signs of decay like mold, sprouts, green color, shriveling, or foul odors. Store potatoes properly to avoid spoilage. Cook potatoes thoroughly and avoid eating the peels of potatoes that taste bitter.

Seeking medical treatment promptly can help prevent complications if illness occurs after eating a bad potato. When in doubt, remember it’s better to be safe than sorry and throw out potatoes past their prime.

Symptom Onset Duration Severity
Nausea 1-6 hours after ingestion 24-48 hours Mild to moderate
Vomiting 1-6 hours after ingestion 24-48 hours Mild to moderate
Diarrhea 6-48 hours after ingestion 24-72 hours Mild to severe
Stomach cramps 2-6 hours after ingestion 24-48 hours Mild to severe
Headache 1-6 hours after ingestion 48-72 hours Mild to moderate
Fever 6-72 hours after ingestion 24-48 hours Mild to moderate

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