Disclaimer: the following is for educational & entertainment purposes only!

Now, if you choose to try anything I mention below, you MUST properly identify the plant and ensure it has had no poisons sprayed upon it.

Weeds are everywhere, indeed, many people say they are merely plants that are in the wrong place. I actually sometimes think they are put deliberately in our way for our own good. For instance, in Spring, we have cleavers & dandelion in great proliferation.  

Cleavers (Galium aparine) is a lymphatic herb, fill a 1 litre jar with clean, young Cleavers, pour over cold water & leave overnight. The next morning, before eating or drinking anything, drink a glass of the cold infusion. Decant the rest off, put it in the fridge & drink a glass for 2 more mornings. Only do this once in spring.
The Italians eat a dandelion leaf salad, or wilt them quickly as one would spinach; as an aperitif, it stimulates the digestion. For a salad, pick a small handful of leaves for each person, dressed with lemon juice & olive oil.

Ensure you make your infusions in a non metal pot, either ceramic or glass, and steep the plant material for 15 minutes.

Chickweed is one of the most useful plants for your skin. Made into an infusion with Lavender flowers it makes a very soothing wash. Cool this infusion before use.
a handful of fresh chickweed popped straight on a sunburn can be soothing.

This is a wee sample of my writing about how useful plants really are, for more, go have a look at Downinedin Magazine, here's the latest: https://bit.ly/giftsinthegarden

and below is a talk from 2010