Green potatoes: Are they OK to eat?

They're probably OK to eat, if you cut or peel off the green parts. Potatoes turn green due to prolonged exposure to light. The green color is due to the presence of chlorophyll, a natural plant pigment.

Although chlorophyll is tasteless and harmless, a potentially toxic substance called solanine develops in the same areas as the chlorophyll. In rare cases, solanine can make you sick, causing signs and symptoms such as nausea and diarrhea. However, most of the solanine is in or under the skin. So peeling the potato removes a good amount of it. If you're very concerned, don't eat potatoes that have green areas.

Solanine increases in potatoes as they age, sprout or bruise. To reduce greening in potatoes, store them in a dark, dry, cool place. Don't keep them in the refrigerator. The chilly temperatures will speed up conversion of potato starch to sugar, which makes potatoes less tasty and causes them to darken.