What if I already ate some?
The short answer It depends on what you see
It depends on how you feel. If you notice double or blurry vision, drooping eyelids, trouble swallowing, speaking or breathing, or weakness, go to the emergency room right away: it may be botulism. If you feel fine, eat no more, set the jar aside and watch for symptoms over the next 8 days.
Reviewed October 26, 2026 · 23 facts, each with its source
When in doubt, throw it out. Fervida can’t see your jar. No page can tell you something is safe: it can show you how to look.
What you see
You ate from a jar and then saw something you didn't like: mold, a rotten smell, a bulging lid. Or you found out you shouldn't have: it was garlic in honey, or a preserve you don't trust.
Why it happens
What matters most is botulism. It's a serious illness, but an uncommon one. It's caused by a toxin that forms in food without oxygen, and its most common sources are homemade foods that were improperly preserved or fermented. Acidity holds it back: the bacterium doesn't grow at a pH below 4.6.
The toxin can't be seen, smelled or tasted, so a jar that seemed fine doesn't rule it out. It doesn't spread from person to person.
Spoiled food can also cause more ordinary food poisoning: diarrhea, stomach pain or cramps, nausea, vomiting and fever.
What to do
It depends on how you feel
Go to the emergency room or your doctor right away if any of these signs show up, in you or in anyone who ate from the jar:
- Double or blurry vision, drooping eyelids or trouble moving the eyes.
- Trouble swallowing, speaking or breathing.
- Muscle weakness.
It can start with marked fatigue, weakness and dizziness, sometimes with vomiting, nausea, stomach pain or diarrhea. Not every sign has to appear at once, and there's no fever. Don't wait: it's a medical emergency. Say what you ate and when. The treatment, an antitoxin, works best the sooner it's given, and most people recover if it's diagnosed and treated early.
In an infant, the signs are different: constipation, poor feeding, drooping eyelids, pupils slow to react to light, less expression in the face and a weak cry that sounds different than usual. See a doctor right away.
If you feel fine:
- Eat no more from that jar, and don't taste it to see if it's fine.
- Close it tightly, mark it so nobody eats it and set it aside. If someone gets sick, it can be tested and help prevent more cases.
- Watch for those signs. They usually appear 12 to 36 hours after eating, but can take anywhere from 4 hours to 8 days. After 8 days without symptoms, throw the jar out.
If you have diarrhea or vomiting but none of the signs above, drink plenty of fluids. See a doctor if there's blood in the diarrhea, if it lasts more than 3 days, if your fever is over 102 °F, if you vomit so often you can't keep liquids down, or if you notice signs of dehydration: peeing little, a dry mouth and throat, or feeling dizzy when you stand up. If you're pregnant and have a fever, see a doctor too.
How to avoid it next time
- Don't eat anything if you don't know whether it was safely preserved or fermented. When in doubt, throw it out.
- Don't taste a jar to find out if it's fine: the taste won't tell you.
- In ferments, acidity is what holds botulism back. If you have strips or a pH meter, make sure it reaches 4.6 or lower before you eat it.
Where every figure comes from
Every statement on this page comes from a food safety guide. We keep a copy of each source and quote its exact words, in its original language.
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1
Botulism is a serious but uncommon illness
“El botulismo es una enfermedad grave pero infrecuente.”
Instituto de Salud Carlos III, Centro Nacional de Epidemiología (RENAVE) · Informe de botulismo 2023 · read on October 25, 2026
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2
Most people recover if it's diagnosed and treated early
“La mayoría de los casos se recuperan si son diagnosticados y tratados precozmente.”
Instituto de Salud Carlos III, Centro Nacional de Epidemiología (RENAVE) · Informe de botulismo 2023 · read on October 25, 2026
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3
Common sources are homemade foods that were improperly canned, preserved or fermented
“Common sources of foodborne botulism are homemade foods that have been improperly canned, preserved, or fermented.”
CDC · Botulism prevention: home-canned foods · read on October 26, 2026
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4
Botulinum toxin can't be seen, smelled or tasted
“You cannot see, smell, or taste the toxin that causes botulism.”
CDC · Botulism prevention: home-canned foods · read on October 26, 2026
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5
Never taste food to find out if it's fine
“Never taste food to see if it's safe.”
CDC · Botulism prevention: home-canned foods · read on October 26, 2026
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6
The botulism bacterium doesn't grow at a pH below 4.6
“Clostridium botulinum no se desarrolla en condiciones de acidez (pH inferior a 4,6)”
Agencia Española de Seguridad Alimentaria y Nutrición (AESAN) · Botulismo (ficha informativa, 30/08/2019) · read on October 26, 2026
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7
Leftovers of the suspect food are kept in an airtight container to be tested and to prevent more cases
“Las muestras de alimentos vinculados a casos sospechosos se deben obtener inmediatamente, guardar en envases herméticos y enviar al laboratorio para identificar la causa y prevenir otros casos.”
Agencia Española de Seguridad Alimentaria y Nutrición (AESAN) · Botulismo (ficha informativa, 30/08/2019) · read on October 26, 2026
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8
Botulism doesn't spread from person to person
“Person to person transmission of botulism does not occur.”
World Health Organization · Botulism: fact sheet · read on October 26, 2026
Show the remaining 15 claims
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9
At first, marked fatigue, weakness and dizziness; then blurry vision, dry mouth and trouble swallowing and speaking
“Early symptoms include marked fatigue, weakness and vertigo, usually followed by blurred vision, dry mouth and difficulty in swallowing and speaking.”
World Health Organization · Botulism: fact sheet · read on October 26, 2026
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10
There's no fever and no loss of consciousness
“There is no fever and no loss of consciousness.”
World Health Organization · Botulism: fact sheet · read on October 26, 2026
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11
Diagnosis rests mainly on what the patient reports and on the examination
“Diagnosis is usually based on clinical history and clinical examination”
World Health Organization · Botulism: fact sheet · read on October 26, 2026
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12
Antitoxin is given as soon as possible, and giving it early reduces deaths
“Antitoxin should be administered as soon as possible after a clinical diagnosis. Early administration is effective in reducing mortality rates.”
World Health Organization · Botulism: fact sheet · read on October 26, 2026
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13
Symptoms usually appear 12 to 36 hours later, at least 4 hours and at most 8 days
“Symptoms usually appear within 12 to 36 hours (within a minimum and maximum range of 4 hours to 8 days) after exposure.”
World Health Organization · Botulism: fact sheet · read on October 26, 2026
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14
The most common symptoms of food poisoning are diarrhea, stomach pain or cramps, nausea, vomiting and fever
“The most common symptoms include diarrhea, stomach pain or cramps, nausea, vomiting, and fever.”
CDC · Symptoms of food poisoning · read on October 26, 2026
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15
With diarrhea or vomiting, drink plenty of fluids to avoid dehydration
“If you have diarrhea or vomiting, be sure to drink plenty of fluids to prevent dehydration”
CDC · Symptoms of food poisoning · read on October 26, 2026
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16
See a doctor for bloody diarrhea, diarrhea over 3 days, a fever over 102 °F, vomiting you can't keep liquids down through, or signs of dehydration
“See a doctor if you have any symptoms that are severe, including: Bloody diarrhea Diarrhea that lasts more than 3 days High fever (temperature over 102°F) Vomiting so often that you cannot keep liquids down Signs of dehydration, which include not urinating (peeing) much, a dry mouth and throat, and/or feeling dizzy when standing up”
CDC · Symptoms of food poisoning · read on October 26, 2026
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17
Pregnant with a fever, see a doctor
“See your doctor if you are pregnant and have a fever and other flu-like symptoms.”
CDC · Symptoms of food poisoning · read on October 26, 2026
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18
Trouble swallowing, muscle weakness, double or blurry vision, drooping eyelids, slurred speech, trouble breathing or moving the eyes
“Difficulty swallowing Muscle weakness Double vision Drooping eyelids Blurry vision Slurred speech Difficulty breathing Difficulty moving the eyes”
CDC · Botulism: symptoms · read on October 26, 2026
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19
There may also be vomiting, nausea, stomach pain or diarrhea
“Signs and symptoms in foodborne botulism also might include: Vomiting Nausea Stomach pain Diarrhea”
CDC · Botulism: symptoms · read on October 26, 2026
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20
Not every symptom has to appear at the same time
“People with botulism might not have all of these signs and symptoms at the same time.”
CDC · Botulism: symptoms · read on October 26, 2026
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21
In an infant: constipation, poor feeding, drooping eyelids, slow pupils, less facial expression and a weak cry
“Signs and symptoms in an infant might include: Constipation Poor feeding Drooping eyelids Pupils that are slow to react to light Face showing less expression than usual Weak cry that sounds different than usual”
CDC · Botulism: symptoms · read on October 26, 2026
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22
Botulism is a medical emergency: with symptoms, see a doctor or go to the ER right away, without waiting
“Botulism is a medical emergency. If you or your child has signs and symptoms of botulism, immediately see your doctor or go to the emergency room. Do not wait.”
CDC · Botulism: symptoms · read on October 26, 2026
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23
Don't eat food if you don't know whether it was safely preserved or fermented
“Do not eat food if you do not know whether it was safely canned, preserved, or fermented.”
Centers for Disease Control and Prevention (CDC) · Botulism Prevention · read on October 25, 2026