As many other users have said, curly dock is an wild edible. For more info, see this profile by Dr. Mark “Merriwether” Vordderbruggen. In fact, the vegetable common garden sorrel, Rumex acetosa, is part of the same genus. I suppose if you catch young plants where they aren’t welcome, it wouldn’t hurt to toss them in a salad. Seeds are good too, if you can separate them from their husks.
A dock I observed in my area
While some people sound the alarm over the oxalic acid in the plant (kidney stones), a lot of other vegetables like celery and spinach also have significant oxalic acid content, so it should only be a concern if consuming in large amounts or if you’re prone to kidney stones.
What really interests me about Rumex, though, is the alleged soothing effect it has with stinging nettle. I say alleged because the exact reason behind its sting-relieving is not known or backed with science (one theory is that dock leaf sap is basic, which neutralizes the acidity in the nettle sting, but this is not true), and there is a lot of contradictory information from many different sources
However, unlike a lot of other herbal remedies, there is not just significant history behind this, but also popular backing from a lot of people, who even today swear themselves on it. Probably wouldn’t do good to rub the leaf really hard since that’ll just irritate things more, but the sap might have something in it. I believe it may also work with other forms of irritation as well like poison ivy or mosquito bites (I once tried crushing the leaves and applying it on some recurring itch on my leg… it helped to the point where I forgot about that itch ten minutes later).
Granted, the truth behind this is murky and there probably other plants that help with nettle stings. However, the discussion itself is interesting enough that whenever I see a dock, I have an itch (pun intended) to take the leaves and grind them into a poultice to see if it works. That is reason enough for me to keep it around
If you don’t want it around, what I would do is strip off all the leaves, grind them up, and then try to use it on any mosquito bite, plant rash, or itch you may be having. Though… I suppose what I would do is not what most normal people would do.
Last note: As others have said, there are probably many other plants that are more menacing than curly dock. For example, Giant Hogweed (Heracleum mantegazzianum) is not only invasive in the Americas, but if you get your skin in contact with the sap, it will strip away the skin’s natural barrier protecting it from UV light, resulting in severe burns when the skin is exposed to sunlight. Search it up… it’s not a pretty picture.