Are Sprouted Potatoes Safe to Eat?

The Bottom Line

You're better off tossing potatoes that have turned green or grown sprouts. Eating them puts you at risk for potential toxicity from solanine and chaconine, two natural toxins found in green or sprouted potatoes.

The Full Story

Many of us have been guilty of buying a huge bag of potatoes, using a few, and leaving the rest sitting in the bag for a month before we remember they're still there. Now the month-old potatoes are green and have little sprouts growing out of them. Why are they green? Are the sprouts poisonous? Can you still eat them?

Potatoes contain two kinds of glycoalkaloids, both natural toxins, called solanine and chaconine. Exposure to light greatly increases the formation of chlorophyll and glycoalkaloids. Chlorophyll is responsible for the green color of many plants and is not toxic. However, the green of chlorophyll is a marker that can indicate that there could be an excess of glycoalkaloids.

The entire potato plant contains glycoalkaloids, but the highest concentration is found in the leaves, flowers, "eyes," green skin, and sprouts. The lowest concentration is found in the white body of the potato. Toxicity is increased by physical injury to the plant, immaturity (green potato), low storage temperature, and storage in bright light. Cooking potatoes by baking, boiling, frying, and microwaving does not eliminate glycoalkaloids. However, removing the skin before cooking can reduce the glycoalkaloid content in a raw potato.

Both solanine and chaconine cause toxicity through cell disruption leading to gastrointestinal symptoms such as vomiting, abdominal pain, and diarrhea. Some people may also experience headache, flushing, confusion, and fever. There have been a few cases of death from eating toxic potatoes. The onset of symptoms is typically within a few hours but can be as delayed as long as a day.

The majority of patients with mild symptoms can remain at home. If symptoms are severe and persistent or if you are unable to hold down fluids, medical attention might be needed.

Glycoalkaloid toxicity from potatoes can be minimized by only buying potatoes as you need them, storing them in a cool and dry place, and peeling them before eating them. The advice for avoiding any type of foodborne illness applies to potatoes: when in doubt, throw them out.

If you suspect someone is having symptoms from eating a bad potato, check the webPOISONCONTROL® online tool for guidance or call Poison Control at 1-800-222-1222.

Diana M. Pei, PharmD
Certified Specialist in Poison Information


For More Information

Smith A. Horrific tales of potatoes that caused mass sickness and even death. Washington (DC): Smithsonian; 21 Oct 2013 [cited 2 Mar 2019].


References

Barceloux DG. Potatoes, tomatoes, and solanine toxicity (Solanum tuberosum L., Solanum lycopersicum L.). Dis Mon. 2009 Jun ;55(6):391-402.

Knuthsen P, Jensen U, Schmidt B, Larsen IK. Glycoalkaloids in potatoes: content of glycoalkaloids in potatoes for consumption. J Food Comp Analysis. 2009 Sep;22(6):577-81.

Mensinga TT, Sips AJ, Rompelberg CJ, van Twillert K, Meulenbelt J, van den Top HJ, van Egmond HP. Potato glycoalkaloids and adverse effects in humans: an ascending dose study. Regul Toxicol Pharmacol. 2005 Feb;41(1):66-72.

Smith A. Horrific tales of potatoes that caused mass sickness and even death. Washington (DC): Smithsonian; 21 Oct 2013 [cited 2 Mar 2019].

Poisoned?

Call 1-800-222-1222 or

HELP ME online

Prevention Tips

  • Buy potatoes shortly before you need them.
  • Inspect potatoes, looking for sprouts and green peels.
  • Store potatoes in a cool, dark place.
  • Remove potato skins before eating.
  • If in doubt, throw it out!

This Really Happened

Case 1. A husband and wife had green potatoes for breakfast. Three hours later, the wife had diarrhea and nausea while the husband remained fine. She was able to stay at home and stay hydrated. Eight hours after breakfast the wife started to feel better.

Case 2. A 42-year-old man arrived at an emergency room after eating potatoes with sprouts on them. He had nausea, vomiting, and dizziness. He was given intravenous fluids, anti-vomiting medication, and an anti-anxiety medication. He was admitted to the hospital for further monitoring and care. He was discharged after 3 days.