Seeing a green potato in your pantry can be alarming, but the green color itself is not the main concern. Potatoes develop green coloring when exposed to light because they produce chlorophyll, which is harmless. However, light exposure can also increase levels of solanine, a naturally occurring toxin that may cause nausea, stomach cramps, headaches and other digestive symptoms when consumed in large amounts. The important thing is knowing when a potato can still be used and when it is better to throw it away.

If a potato is firm and has only a few small green areas, it may not need to be discarded. Peel the potato deeply, removing the skin and all visible green areas, and cut away any eyes or sprouts. However, potatoes that are extensively green, soft, shriveled or noticeably bitter should be discarded. Cooking does not reliably eliminate solanine, so boiling, baking or frying should not be viewed as a way to make a badly affected potato safe.

Proper storage can help prevent potatoes from turning green in the first place. Keep them in a cool, dark, dry and well-ventilated location, preferably in a paper bag, pantry basket or another container that allows air to circulate. Exposure to light and warmth encourages both greening and sprouting. It is also best to keep potatoes away from onions, which can contribute to faster spoilage and sprouting. Raw potatoes generally should not be refrigerated because cold temperatures can alter their starches and affect their flavor and cooking quality.

There is no need to panic when you notice a small amount of green on a potato. Instead, inspect it carefully before deciding what to do. Remove small green areas and sprouts from firm potatoes, but discard potatoes that are heavily green or showing signs of deterioration. Buying only what you can use within a reasonable period and checking your supply regularly can also reduce waste. When a potato looks questionable, throwing it away is the safest choice.