Green Potatoes: Are They Safe to Eat? What to Do When Your Potatoes Turn Bright Green Under the Skin
You peel a few potatoes for dinner, expecting the familiar creamy yellow or white flesh—and suddenly you see something completely different: a bright green layer underneath the skin.
That is exactly the situation shown in the photo above.
The natural reaction is to wonder: Can I simply peel away the green part, cook the potatoes, and carry on with dinner? Or should the potatoes go straight into the trash?
The short answer is that green potatoes deserve caution. The green color itself is not the poison, but it can be a warning sign that the potato contains increased levels of naturally occurring compounds called glycoalkaloids, particularly solanine and chaconine. In sufficiently high amounts, these compounds can cause illness.
For the potatoes shown in the photo, the green discoloration appears quite pronounced and extends beyond a tiny patch immediately beneath the skin. In that situation, I would not use them for mashed potatoes. There are safer alternatives for dinner, even if that means changing the meal.
Let's look at why potatoes turn green, whether peeling helps, whether cooking destroys the toxins, what symptoms to watch for, and how to prevent the problem in the future.
Why Do Potatoes Turn Green?
Potatoes naturally contain compounds known as glycoalkaloids. The two principal ones are alpha-solanine and alpha-chaconine.
These compounds are part of the potato plant's natural defense system. Under normal circumstances, the levels present in the edible portion of a healthy potato are low. Problems can occur when potatoes are exposed to conditions that encourage glycoalkaloid production.
One of the biggest factors is light.
When potatoes are exposed to sunlight or artificial light, they produce chlorophyll. Chlorophyll is the pigment responsible for the green color. Chlorophyll itself is not considered toxic, but the greening can occur alongside an increase in glycoalkaloids. This is why a green potato should not simply be treated as an ordinary potato with an unusual color.
The green color is therefore useful as a warning sign.
Other factors can also contribute to increased glycoalkaloid levels, including aging, physical damage and certain storage conditions. The compounds tend to be concentrated more heavily in the peel, areas immediately beneath the peel, sprouts and damaged or green portions of the potato.
That explains why you may peel a potato and discover that the flesh directly underneath the skin has a green or greenish-yellow appearance.
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Is the Green Color Itself Dangerous?
This is an important distinction.
Chlorophyll is not what makes a green potato potentially harmful.
Chlorophyll is simply the pigment responsible for the green appearance. The concern is that greening can indicate that the potato has also developed higher concentrations of glycoalkaloids.
In other words, you cannot look at the color alone and calculate exactly how much solanine or chaconine is present.
Two potatoes that look slightly green may not contain exactly the same concentration. Potato variety, growing conditions, storage and exposure to light can all influence glycoalkaloid levels.
Nevertheless, pronounced greening is a good reason to be cautious.
Health Canada advises consumers to avoid potatoes showing signs of greening, damage, rot or sprouting, and specifically recommends removing green areas before cooking. It also advises discarding potatoes with pronounced greening or damage.
Can You Just Peel the Green Skin Off?
Sometimes the answer depends on how extensive the greening is.
Glycoalkaloids are found throughout the potato, but the highest concentrations tend to occur in the peel and the tissue immediately underneath it. Consequently, removing the peel and cutting away green portions can reduce exposure.
This is why a potato with a very small, superficial green area is different from a potato that is visibly green over a substantial portion of its surface.
If you notice a tiny green patch, you can peel the potato and cut away the green and surrounding affected tissue rather than simply shaving off the thinnest possible layer.
But the potatoes in the photograph are more concerning because the green color is clearly visible underneath the skin and covers a substantial area.
In that situation, there is no good reason to gamble on whether enough of the affected tissue has been removed.
A useful rule of thumb
Think about it this way:
- No greening: normal preparation is appropriate.
- Tiny, superficial green area: peel thoroughly and cut away the green portion.
- Large or pronounced green areas: discard the potato.
- Green potato combined with extensive sprouting, rot or damage: discard it.
- Bitter taste or burning sensation after cooking: do not eat it.
Health Canada specifically recommends discarding potatoes with pronounced greening, while Poison Control takes the more conservative position that potatoes that have turned green or developed sprouts are better thrown away.
Does Cooking Destroy the Toxins?
This is one of the most important points—and one of the most common misconceptions.
You might think:
"I'm going to boil these potatoes for mashed potatoes anyway, so won't the heat make them safe?"
Unfortunately, ordinary cooking should not be relied upon to eliminate potato glycoalkaloids.
Health Canada states that glycoalkaloids are not destroyed by normal cooking, including frying. Its food-safety guidance explains that boiling, baking, microwaving and frying do not reduce glycoalkaloid concentrations to a meaningful degree.
That means boiling green potatoes for mashed potatoes isn't a reliable solution.
The same applies to:
- Baking them
- Roasting them
- Frying them
- Microwaving them
- Turning them into mashed potatoes
- Making soup from them
Cooking can make potatoes softer and more pleasant to eat, but it should not be considered a method for removing excessive glycoalkaloids.
This is why simply thinking, "I'll cook them really well," isn't the right approach to significantly green potatoes.
What Happens If You Eat Too Many Green Potatoes?
The potential problem is glycoalkaloid toxicity.
Eating potatoes containing sufficiently high concentrations can cause gastrointestinal symptoms such as:
- Nausea
- Vomiting
- Abdominal pain
- Diarrhea
Other symptoms can occur in more serious cases, including headache, flushing, confusion, weakness and other neurological effects. Poison Control notes that symptoms can begin within a few hours, although they can sometimes be delayed for considerably longer.
A bitter taste or a burning sensation in the mouth is also an important warning sign. Health Canada advises that potatoes producing this bitter or burning sensation should not be consumed.
This doesn't mean that accidentally eating one bite of a slightly green potato will automatically make someone sick. Toxicity depends on the amount of glycoalkaloids consumed, and concentrations vary considerably between potatoes.
The important point is that there is no advantage to knowingly eating a heavily green potato when you have the option of choosing another food.
What Would I Do With the Potatoes in the Photo?
If these were the potatoes I had prepared for dinner, I would discard them rather than make mashed potatoes from them.
The reason isn't that every tiny trace of green automatically means a potato is poisonous. The issue is that the greening shown here is substantial enough that I wouldn't consider it worth taking the chance.
The green tissue is clearly visible after peeling, rather than being a tiny spot that can easily be removed.
And because cooking does not reliably destroy glycoalkaloids, boiling them into mashed potatoes wouldn't solve the underlying problem.
If these were the only potatoes in the kitchen, I would change the side dish rather than try to rescue them.
Depending on what was available, alternatives could include:
- Rice
- Couscous
- Pasta
- Bread
- Bulgur
- Polenta
- Sweet potatoes that look normal
- Other vegetables
- A simple salad or vegetable side
It might be disappointing to change dinner plans, but wasting a few potatoes is preferable to deliberately consuming food that shows pronounced greening.
What If You Already Peeled and Cut Them?
Don't panic.
Simply discovering that a potato has green tissue does not mean you have been poisoned.
If you haven't eaten it yet, the easiest decision is simply not to use it if the greening is extensive.
If you ate a small amount before noticing the discoloration, pay attention to how you feel. Most people with mild symptoms can generally remain at home and stay hydrated, according to Poison Control. However, severe or persistent symptoms—or an inability to keep fluids down—are reasons to seek medical attention.
If someone develops concerning symptoms after eating suspected toxic potatoes, contacting a local poison-control service or medical professional is appropriate. Emergency symptoms should be treated as an emergency rather than waiting to see whether they disappear.
The important thing is not to assume that a symptom is definitely caused by the potato. Nausea, vomiting and abdominal discomfort can have many causes.
How Should Potatoes Be Stored to Prevent Greening?
Prevention is much easier than dealing with green potatoes at dinnertime.
The biggest thing to remember is:
Keep potatoes in a cool, dark, dry place.
Light encourages greening and is associated with increased glycoalkaloid production.
A pantry, cupboard or other appropriately cool and dark storage area is generally preferable to leaving potatoes exposed on a kitchen counter where sunlight can reach them.
You should also avoid storing potatoes in conditions that encourage deterioration.
Inspect your potatoes periodically and use older potatoes before they become heavily sprouted, damaged or green.
It is also useful to buy quantities that you can reasonably use before they deteriorate. Poison Control recommends buying potatoes relatively close to when you intend to use them and checking them for green skin and sprouts.
Should You Refrigerate Potatoes?
This question is slightly more complicated because different food-quality considerations are involved.
The key advice for preventing greening is to keep potatoes away from light and store them appropriately rather than leaving them exposed.
The FDA also advises storing potatoes outside the refrigerator, preferably in a dark, cool place, partly because refrigeration can increase sugar formation that may contribute to acrylamide formation when potatoes are cooked at high temperatures.
So for everyday home storage, a dark, cool pantry or suitable storage area is generally a practical choice.
What About Potato Sprouts?
Sprouts are another warning sign.
Potatoes naturally produce sprouts as they age and begin trying to grow a new plant. Sprouted potatoes can contain higher levels of glycoalkaloids, particularly in the sprouts and surrounding areas.
If a potato has only a very small amount of sprouting and otherwise looks normal, some food-safety guidance allows removal of the sprouts and surrounding affected tissue.
However, if the potato is heavily sprouted, green, shriveled or damaged, throwing it away is the safer choice.
A potato showing multiple warning signs is not something I would try to salvage for an important meal.
What Does a Bitter Potato Taste Like?
Taste can sometimes provide an additional warning, but it shouldn't be your primary safety test.
Potatoes with elevated glycoalkaloids can have an unpleasant bitter taste or cause a burning sensation in the mouth. Health Canada specifically identifies these sensations as warning signs and recommends not eating potatoes that taste bitter or produce a burning sensation after cooking.
But don't deliberately eat a large portion of a suspicious potato just to "test" it.
If you've already cooked potatoes and the flavor seems unusually bitter or produces a burning sensation, stop eating them.
Are Green Potatoes the Same as Rotten Potatoes?
No.
Greening and rotting are different problems.
A potato can be green while otherwise firm and free of visible mold or decay. The concern in that case is primarily the increased concentration of glycoalkaloids associated with greening.
Rotting potatoes present a different food-safety problem and should also be discarded.
The two conditions can occur together, however. If a potato is green and soft, moldy, leaking, badly damaged or rotten, there is even less reason to try to save it.
The FDA generally advises consumers to cut away damaged or bruised areas on fresh produce and throw away produce that appears rotten.
What Should You Do Before Peeling Potatoes?
Even if you're planning to remove the skin, washing the potatoes first is a good habit.
The FDA recommends washing fresh produce thoroughly under running water before preparing or eating it, even when you don't plan to eat the skin. This helps prevent dirt and microorganisms on the outside from being transferred to the edible interior while cutting or peeling.
You don't need to wash potatoes with soap or household detergent. The FDA specifically advises against doing so.
A simple routine is:
- Wash the potato under running water.
- Inspect it for green areas, sprouts, damage and rot.
- Peel it if desired.
- Cut away any questionable green or damaged areas.
- If greening is extensive, discard the potato rather than trying to salvage it.
Why Does the Green Sometimes Appear Only After Peeling?
This can be surprising.
A potato may look relatively normal from the outside while the tissue directly underneath the skin has a greenish color.
The outer brown skin can hide discoloration underneath it. That's why peeling can reveal something that wasn't obvious when you first looked at the potato.
This is particularly relevant to potatoes with russet or brown skins, because the external appearance can make subtle greening difficult to notice. Health Canada notes that some potato skins can camouflage greening.
So if you see green after peeling, don't assume that the potato suddenly "became" green. The discoloration may simply have been hidden beneath the skin.
Can You Prevent Potatoes From Turning Green?
Yes, and the main strategy is remarkably simple: keep them away from light.
When you bring potatoes home:
1. Store them somewhere dark
Avoid leaving them in direct sunlight or underneath bright kitchen lighting for long periods.
2. Keep them reasonably cool and dry
Avoid excessively warm or damp storage conditions.
3. Don't buy more than you can use
Older potatoes are more likely to sprout and deteriorate.
4. Inspect them before cooking
Check for:
- Green skin
- Green flesh beneath the skin
- Sprouts
- Soft spots
- Rot
- Significant damage
5. Don't ignore bitterness
An unusually bitter potato or one that causes a burning sensation should not be eaten.
The Bottom Line: Would You Eat the Potatoes in the Picture?
For the potatoes shown in the image, I would throw them away.
The green discoloration is not merely a tiny spot on the surface. There is a noticeable green layer underneath the skin, and the affected area appears extensive.
That doesn't mean that every green potato is automatically poisonous, nor does it mean that anyone who accidentally ate some green potato will necessarily become ill. The actual concentration of glycoalkaloids varies between potatoes.
But pronounced greening is a recognized warning sign, and official food-safety guidance recommends avoiding potatoes with significant greening and discarding those with pronounced discoloration.
Most importantly, don't assume that boiling them for mashed potatoes will remove the problem. Glycoalkaloids are relatively heat-stable and ordinary cooking does not reliably eliminate them.
So if you're standing in the kitchen with a pile of green potatoes and thinking, "But these are the only ones I have," the safest practical answer is to change the dinner plan.
A missing side dish is frustrating.
A potentially unpleasant case of food poisoning is much less convenient.
When potatoes are only slightly affected, removing the green portions may reduce exposure. When the greening is pronounced—as it appears to be in this photograph—the safer choice is to discard them and use something else for dinner.
