On a different question on rhubarb, a link to the wikipedia-page was posted. It is stated there that cooking rhubarb leaves with soda can make them more poisonous.

Does the same hold true for cooking the rhubarb stem and adding soda? Up until know, I thought it was a nice and easy way to reduce the sour taste a bit.

  • I think the same caveat from the other question applies here. The leaves aren't strictly poisonous - they're toxic in large quantities. The stems aren't completely safe - they're also toxic in much larger quantities. Soda will increase the toxicity of both, but the starting point is a lot lower if you're cooking the stems. If you've been doing this already and you haven't gotten sick, that's a good sign, but the exact risk is difficult to quantify. Probably best to avoid for infants, elderly, and pregnant eaters just in case.
    – logophobe
    Apr 22, 2015 at 16:48
  • If you'd convert your answer to an answer, I could upvote it. On topic: No, I don't remember getting sick of it. But then, maybe I got sick and just don't know anymore if I ate rhubarb beforehands...
    – Thaoden
    Apr 22, 2015 at 17:15
  • My vote goes to @rumtscho, whose answer covers the same points - if anything I might propose a couple of edits.
    – logophobe
    Apr 22, 2015 at 17:33
  • There's more than one answer I can upvote...
    – Thaoden
    Apr 23, 2015 at 7:27

1 Answer 1


The whole quote is

Cooking the leaves with soda can make them more poisonous by producing soluble oxalates

I can't tell you if the claim as a whole is true. But if it is true for the leaves, it is true for the stems too.

Rhubarb contains oxalic acid and its salts which are created by the acid reacting with different metal ions such as calcium and magnesium. It's true that these salts have different solubility and bioavailability. And both the leaves and the stems contain oxalic acid and salts, just in different concentration.

So, if cooking the leaves in soda turns the insoluble oxalates in them to soluble ones, then the same will happen when cooking the stems. For the metal ions, it's irrelevant if they are reacting with an oxalate ion which used to "live" in the leaf or in the stem. Anything which makes the leaves worse will also make the stems worse.

  • So... Is it safe to cook rhubarb with soda or am I better off not doing it?
    – Thaoden
    Apr 22, 2015 at 14:40
  • I have no idea. Wikipedia lists an Australian book from 1974 as the source of their claim, I doubt that we can find a copy and look at the reference in detail. And this sentence is too little for further research. Especially, they don't say which oxalates are the old (insoluble) ones and which ones are created when cooking with soda.
    – rumtscho
    Apr 22, 2015 at 14:47

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