Oxalis, particularly Oxalis corniculata (yellow wood sorrel), is a good source of vitamin C and has been used historically to treat scurvy.
We have it growing everywhere it’s not really welcome, as do many other people.
Oxalis has been traditionally used for a variety of other conditions, including fevers, wounds, boils, abscesses, insect bites, burns, digestive issues, stomach cramps, nausea, diarrhoea, digestive aid, thirst quenching, urinary tract infections, hookworms, flu, enteritis, sprains, snakebites, antifungal aid, inflammation, tumours, liver protection, diabetes, and much more.
Just a caution, though, Oxalis contains oxalic acid, which can cause discomfort if consumed in large amounts, especially in people with kidney problems or a tendency toward gout. So, like we should with everything else we consume, use in moderation.
Drink it as a tea, maybe blended with another herb you love?
Just another useful little herb that we treat as a pest.