A potato that has turned green under the skin belongs in the trash, not on your plate. MedlinePlus says never to eat potatoes that are spoiled or green below the skin, and to always throw away the sprouts. The reason is solanine, a poison the encyclopedia calls very toxic even in small amounts.

Solanine is found throughout the potato plant, MedlinePlus says, but especially in green potatoes and new sprouts. Eating those green tubers or new sprouts is what causes potato plant poisoning. The good news is simple: potatoes that are not green and have had any sprouts removed are safe to eat.

If you think someone has eaten a green potato or sprouts, MedlinePlus says to seek medical help right away and not to make the person throw up unless poison control or a health care provider tells you to. The encyclopedia notes that how well someone does depends on how much poison was swallowed and how quickly treatment is received.

Help is a phone call away. The national Poison Help hotline, 1-800-222-1222, connects you with poisoning experts from anywhere in the United States, MedlinePlus says. The service is free and confidential, available 24 hours a day, 7 days a week, and you can call with any question about poisoning or poison prevention, even when it is not an emergency.