Over St. Patrick's Day everything, including beer, has a tinge of green about it but what about Ireland's favorite the humble spud? Should we eat green potatoes?

For some people, it isn’t St. Patrick’s Day unless it begins with a bagel as green as the Wicked Witch of the West and ends with knocking back one last pint of emerald beer.

There are all sorts of other green treats – courtesy of both nature and food coloring – to keep you in the Irish spirit throughout the day, but there’s one Irish favorite you must avoid at all costs is green: potatoes.

What was commonly known in past generations is now often thought to be an old wives' tale, but it’s true – green potatoes are poisonous.

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Potatoes (solanum tuberosum) turn green and produce sprouts when exposed to sunlight or extreme temperatures. The green itself is chlorophyll and is totally harmless, but indicates increased levels of a toxin called solanine.

Green Potatoes: What do you think?    (Via: Flickr / Philip K Kalina.)

Green Potatoes: What do you think? (Via: Flickr / Philip K Kalina.)

All potatoes produce solanine as a defense against pests and fungus. Eating potatoes with high levels of solanine can cause potato plant poisoning.

According to the National Institute of Health-run website Medicine Plus, symptoms of potato plant poisoning include delirium, fever, hallucinations, headache, vision changes, nausea, vomiting, shock, loss of sensation and a drop in body temperature.

Potatoes that are green in parts and only lightly sprouted can be remedied – just cut away the sprouts and green areas until all margins are clear.

Read more: Colcannon to quiche - celebrate St. Patrick's Day with these Irish potato recipes

Potatoes that are fully green, however, should be discarded. A study from the University of Nebraska at Lincoln revealed that 16oz of fully green potato (the size of a medium to large baked potato) would be enough to poison a person weighing 100 pounds. The bitter taste of green potatoes is also a natural deterrent.

While some studies have shown the temperatures reached when potatoes are deep-fried to be enough to lessen the levels of solanine, boiling potatoes has little to no effect on the toxin.

If you simply must have green spuds, here’s a delicious and healthy take on Irish-Italian mashed potatoes, using dandelion greens (you can also use spinach) to create the green potato effect.


Read more: IrishCentral's most popular potato recipe

* Originally published in March 2015.

True or false? Green potatoes are poisonous.iStock