Why are you not supposed to eat sprouted potatoes?

December 7, 2025 •

3 min read

According to toxicologists, sprouted potatoes contain elevated levels of naturally occurring toxins called glycoalkaloids. This is why you are not supposed to eat sprouted potatoes, as these toxins can cause mild to severe illness, depending on the quantity consumed.

Quick Summary

Sprouted potatoes contain increased levels of glycoalkaloids, like solanine, which can be toxic if consumed in large quantities. The sprouts, skin, and any green areas hold the highest concentration of these compounds, posing a health risk. This toxicity can cause symptoms ranging from gastrointestinal upset to severe neurological issues.

Key Points

Sprouts are toxic: Potato sprouts contain high concentrations of glycoalkaloids, primarily solanine, which is toxic to humans.
Greening signals toxicity: A green tint on a potato's skin indicates increased levels of solanine, not just harmless chlorophyll.
Cooking doesn't destroy toxins: High-temperature cooking methods like boiling or frying do not effectively eliminate solanine from potatoes.
Toss spoiled potatoes: If a potato is soft, shriveled, or has extensive greening and long sprouts, it should be discarded entirely.
Practice safe storage: Store potatoes in a cool, dark, and well-ventilated space, away from sunlight and other produce like apples, to prevent sprouting.
Symptoms of poisoning: Solanine poisoning can cause nausea, vomiting, abdominal pain, and, in rare cases, more severe neurological symptoms.
When in doubt, throw it out: Given the potential health risks, it is safest to discard any potato that shows significant signs of sprouting or greening.

The Chemical Culprit: Glycoalkaloids and Solanine

Potatoes are part of the nightshade family, which naturally produces toxic compounds known as glycoalkaloids as a defense mechanism against insects and fungi. The two main types are solanine and chaconine. In a fresh, healthy potato, these compounds are present in very small, harmless amounts. However, when a potato is exposed to light or physical damage, or simply ages, it begins to produce higher concentrations of these toxins. This is an innate survival response, signaling the potato to start growing a new plant rather than being eaten.

When a potato sprouts, the glycoalkaloid levels skyrocket, particularly in the sprouts themselves, the potato's 'eyes,' and the skin. The same is true for potatoes that turn green. While the green color comes from harmless chlorophyll, its presence is a clear indicator that solanine production has also increased significantly. Consuming these high-concentration areas can lead to a condition known as solanine poisoning.

Symptoms of Solanine Poisoning

Symptoms of solanine poisoning typically manifest within 2 to 24 hours after ingesting toxic potatoes. The severity depends on the amount of toxins consumed. Mild cases usually involve gastrointestinal discomfort, while severe poisoning can affect the central nervous system and requires immediate medical attention.

Common symptoms include:

Nausea and vomiting
Diarrhea and abdominal pain
Headaches and dizziness
A burning sensation in the mouth or throat

In more severe, though rare, cases:

Hallucinations
Loss of sensation and paralysis
Fever and low body temperature
Rapid pulse and low blood pressure

Can You Salvage a Sprouted Potato?

This is a gray area and depends heavily on the potato's condition. For a potato that is still firm, has no greening, and only features small, newly formed sprouts, you may be able to salvage it. However, if the potato is soft, shriveled, or has extensive green patches, it is best to discard it entirely. The bitter taste of high-solanine potatoes is another reliable indicator that it should be thrown away, as cooking does not destroy the toxins effectively.

When to Salvage vs. When to Toss


Condition of Potato	Action	Reason
Firm, small sprouts, no greening	Cut out all sprouts and 'eyes' deeply before cooking.	Toxin concentration is low and mostly contained in the sprouts and eyes.
Firm, extensive greening	Toss or peel very thickly and cook; avoid eating any bitter parts.	Greening indicates higher solanine levels throughout, especially near the skin.
Soft, shriveled, or extensively sprouted	Toss immediately.	High toxin levels are likely present throughout the entire potato.
Any potato with a bitter taste	Toss immediately.	A bitter taste is a strong indicator of high glycoalkaloid concentration.

Preventing Sprouts and Toxin Build-up

Proper storage is the best way to prevent potatoes from sprouting and turning green in the first place. By controlling the environment, you can significantly extend their shelf life and maintain their safety.

Keep them cool and dark: Store potatoes in a cool, dark, and well-ventilated area, like a pantry, cabinet, or cellar. Temperatures between 45–50°F (7–10°C) are ideal.
Avoid sunlight: Light exposure is the main trigger for solanine and chlorophyll production. Keeping them in a paper bag or a box will prevent this reaction.
Do not refrigerate: Storing raw potatoes in the refrigerator can increase their sugar content and may also increase solanine levels.
Ventilation is key: Ensure good air circulation around the potatoes to prevent moisture buildup, which can accelerate sprouting and spoilage.
Separate from other produce: Do not store potatoes near onions or fruits like apples. These can release ethylene gas, which hastens the ripening and sprouting process.
Consume within a reasonable time: Even with proper storage, potatoes will eventually sprout. Use them within a few months of purchase for the best quality and safety.

Conclusion

While a slightly sprouted potato that is still firm and has had all sprouts and green parts removed might be safe to eat for some, the general consensus is to be cautious due to the risk of solanine poisoning. The severity of the risk depends on the degree of sprouting, greening, and overall spoilage. Proper storage is the most effective preventative measure. Ultimately, when in doubt, it is safer to dispose of a questionable potato to avoid any potential health complications from these naturally occurring toxins. A firm, unsprouted, and un-greened potato is a safe potato.

Poison Control offers a free and confidential service for questions about potential poisoning.

Frequently Asked Questions

Solanine is a naturally occurring, toxic glycoalkaloid produced by potatoes and other nightshade plants as a defense mechanism against pests. It is present in low concentrations in healthy potatoes but increases significantly in sprouts, eyes, and green areas.

Yes, if the potato is still firm, not green, and has only small, new sprouts. Cut the sprouts and a wide margin of flesh around them. However, if the potato is soft, shriveled, or heavily sprouted, it's safer to throw it away entirely.

Peeling a green potato removes most of the solanine, which is concentrated near the skin. However, if the green color is extensive or the potato tastes bitter after peeling, it may still contain unsafe levels of the toxin and should be discarded.

No, cooking does not effectively destroy solanine. The toxins are heat-stable, meaning boiling, baking, or frying will not fully remove the health risk associated with high-solanine potatoes.

To prevent sprouting, store potatoes in a cool, dark, and dry place like a pantry or cellar. Avoid direct sunlight and keep them away from other ripening produce, like onions and apples, which release ethylene gas that speeds up sprouting.

The initial symptoms of solanine poisoning usually include gastrointestinal issues such as nausea, vomiting, diarrhea, and stomach cramps. A bitter taste or burning sensation in the mouth can also be an early warning sign.

While severe cases of solanine poisoning are rare, mild gastrointestinal upset from consuming slightly elevated levels of the toxin is more common. Many people recover quickly at home, but it is still a risk to be taken seriously.

If you experience mild symptoms like stomach upset, stay hydrated and rest. For severe or persistent symptoms, or if you are concerned, seek immediate medical attention or call a poison control center.