Wondering where you heard that?? It can contain fairly high amounts of oxalic acid, but that's not poisonous....may interfere with calcium absorption....but you are not going to eat a cup a day for a week are you?
No.....don't believe that's so at all.

Bulldinkie, swiss chard is not poisonous, not even large leaves.

There is a variety of swiss chard called "rhubarb", but it is not the same as the sour rhubarb that we use to make pies. The leaves of the traditional rhubarb ARE poisonous, but the leaves of the rhubarb variety of swiss chard are not.

I've eaten them well into December, and we eat the large stalks cooked separately from the leaves because they take so long to cook, but the big ones are not poisonous. Tougher perhaps.

Annie

Ah. Bulldinkie, iirc, is on dialysis, so possibly has been told to avoid Swiss chard.

Colleen, you are probably right, I know stepmother was on dialysis and wasn't allowed to eat any greens. Now she's on coumadin for her heart and still isn't supposed to eat greens, something about the coumadin level in her blood.

So, it's not poisonous, but it could be unhealthy for people with other health issues, I'm sure.

Annie

Leafy greens and green vegetables contain Vitamin K which aids in blood clotting.
So it isn't really that you don't dare eat greens but you need to eat about the same amount every day....because you coumadin dosage is based on the clotting level of your blood.
So if you take coumadin, don't go crazy when the garden lettuce comes in or your garden yields lots of fresh broccoli, but also don't go on a greens fast either. Consistant ... that's the ticket.
Linda C

There are some conditions where you do need to limit oxalic acid. I have one of them--interstitial cystitis. So I did some research on it. Lots of greens have oxalic acid in them, such as spinach. I love greens so much and they are so healthy otherwise, I eat them anyway. So far they haven't bothered me. I don't eat them to excess. As with all food sensitivities, everyone's mileage may vary, there's a lot of biochemical diversity in humans I am finding out!

The average person would have to eat a very large amount of greens to feel any effects at all.

Thats what the guy said on Good eats, Alton ?? he said when swiss chard gets big it can be poisonous like rhubarb leaves .He said if it tastes bitter do not eat.I just planted 6 plants yellow ,red.

Yes, if you're on dialysis, you need to know greens have high potassium levels. It's one of the things that keeps your heart in check, much like calcium and sodium, and it must be in the right balance. Be careful heart and dialysis patients!

Well....fish is "poisionous" to my SIL....would kill him without an EPI pen, musk melon is poisionous to my daughter, for some salt is poisionous for others things like strawberries or sesame seed rolls.
The oxalic acid in some greens may not be good for those with certain health conditions, but they are not poisionous.

I agree, LindaC, and I seldom disagree with Alton but swiss chard is not poisonous.

Bulldinkie, be sure to run it past your doctor before you eat much of that swiss chard, though, as has been mentioned, many people with chronic health conditions should forego greens. It would be horrible to eat something that's supposed to be so good for you, and find out that it's actually really bad for you.

Annie

I found the Alton Brown script to the program, "Field of Greens" where he uses the word 'toxic'.

However, if you continue to cook the leaves and these nutrients, the nutrients themselves, or some of them, can begin to break down. Bad things can happen. See, when isothiocyanates cook enough, they form very strong flavors and even stronger smells in the air. In fact, that stinky, rotten egg smell that comes out of greens all too often can be toxic in large amounts. In fact, it was synthesized and turned into a biological warfare agent used in World War I called mustard gas. Of course, now that I think about it, I'm pretty sure my mother waged biological warfare on me in the 1960's. I've got to get some air.

Here is a link that might be useful: Field of Greens.

So the smell can be toxic, so much that it can be synthesized into mustard gas, but the greens are not. I guess that makes sense, I've smelled some pretty strong greens cooking!

And kids the world over would agree...

Annie

I don't think cabbage qualifies as "greens" does it? (wink, wink to you Annie!)

My lesson from this thread is that because one can distill a poisonous gas from the leaves of a plant does not mean that the plant is dangerous. Right?

Right. Concentration always matters. At some stage of production, Coke syrup travels with MSDS papers and can cause chemical burns. Pepper spray is made from peppers. What's perfectly safe in small quantities can be lethal in huge quantities.

Robin, that's a good question. Is cabbage considered a green? I never thought of it as a green, but I guess it really is. I always put the cruciferous vegetables in a class by themselves, the cabbage, broccoli, cauliflower, etc.

Hmmmm.....

Annie

Well, in sufficiently large quantities even water is poisonous, as is nutmeg.

Cabbage is a green....the greener the leaves....the greener.

Everyone knows that awful sulfurous odor of overcooked cabbage.....it's what gave the stuff a bad name.
But poisonous?...only to visitors!

That's the kind of thing that gets me about "over scientific"....take a small fact, like mustard gas comes from a substance in plants we eat....and someone can turn it into "be careful because Swiss Chard can poison you".

Swiss chard is apparently poisonous to me. Although I grew up eating it, if I eat it now I get to experience a very violent, painful total system purge similar to the effects of food poisoning.

Sure that it couldn't really be the healthy Swiss chard I'm growing organically in my garden that was causing this food poisoning reaction, I sautéed some chard for supper last night. Suffice it to say, it was a long, most miserable night, and sadly I have crossed chard off of my list of veggies I enjoy.

Sounds like a good cleansing.

When I take my dog to the park and he swims in the harbor and drinks too much salt water while fetching tennis balls...

...well let's just say more than one fellow pet owner, citing vets' opinions, has said "that's supposedly good for him." I never bothered to research to subtantiate.

http://www.whfoods.com/genpage.php?tname=foodspice&dbid=16

Swiss chard is commonly used in Mediterranean culinary. If It's so poisonous why Mediterranean food is knowing to be so healthy as well as their people? I had been eating Swiss chard all my life and I'm as fresh as a green lettuce ( Mediterranean expression). Now... I do agree that can be bad for people with food allergies or food intolerance as well.

I HAVE BEEN GROWING AND EATING SWISS CHARD SINCE I WAS 6 YEARS, MY FIRST GARDEN. MY MAin crop. i am 79. only reason i dont have rhubarb variety is because it cant handle cold, and it bolts in summer. i grow lots of FORDHOOK GIANT, AND LUCULLUS.. I DONT EAT THAT MUCH. I GET 2 CUTTINGS PER MONTH. EACH CUTTING WILL GIVE 6 MEALS. SO ONCE I WASH, I BAG IN ZIP LOCK BAGS AND SET IN MY CRISPER..