Have you ever cut open a potato and noticed a green color underneath the skin? The green itself comes from chlorophyll, which forms when potatoes are exposed to light. However, the same conditions can also be associated with increased levels of natural glycoalkaloids, including solanine and chaconine. In high amounts, these compounds can cause symptoms such as nausea, vomiting, stomach cramps, headaches, and digestive discomfort.

If a potato has only a small amount of green discoloration and is otherwise firm and healthy, you can peel it generously and cut away the green portions, eyes, and sprouts. Don’t simply scrape off a thin layer and assume the problem is gone. If the potato is extensively green, heavily sprouted, soft, shriveled, or otherwise looks spoiled, it is safer to throw it away.

A bitter taste can also indicate that a potato may contain elevated glycoalkaloids, but you should never taste a questionable potato just to test it. If a potato you’ve already prepared tastes unusually bitter or unpleasant, stop eating it and discard it. Cooking, including boiling, baking, or frying, should not be considered a dependable way to remove these compounds from a heavily green potato.

To reduce the chance of potatoes turning green, store them in a cool, dark, dry, and well-ventilated place. Keep them away from sunlight and strong kitchen lighting. Avoid storing potatoes with onions, and check them regularly for sprouts, soft spots, or other signs of deterioration. Buying only what you can use within a reasonable period can also help prevent potatoes from sitting too long.

The easiest rule to remember is simple: a little green does not automatically mean the whole potato must be discarded, but extensive greening is a reason to be cautious. When a potato looks significantly green, feels soft or shriveled, or has other signs of spoilage, throwing it away is the safest choice. When it comes to questionable food, saving one potato is simply not worth the risk.