First things first…NO NIBBLING!
Putting something in your mouth is not part of the identification process; it’s what you do with food. Once you are 100% certain of what you are dealing with, then trying a tiny amount may or may not be the appropriate next step. Tasting an unidentified plant is as dumb as putting a loaded gun in your mouth and pulling the trigger to find out if it contains bullets or not. We promote sensible foraging.
All things in moderation
When trying something new for the first time, only eat a very small amount to make sure there are no adverse effects. We are all wired differently and can respond differently too. Doing a simple tolerance test is a good habit to get into. By way of example, the root of common valerian is used to make a wonderful sedative tincture, rather like a natural valium. However, in about ten per cent of people, it has the polar opposite effect and acts as a stimulant. When trying a new species of mushroom for the first time, having obviously reached the point where I am utterly certain of my ID. I cook and eat a tiny section of one cap, the following day I eat a larger piece, and the day after is when I might consider consuming a whole portion.
Another reason for moderation is simply not to be too greedy. It’s such a good feeling when you find and successfully identify something you know is going to taste great. It’s sometimes really hard not to get carried away, but if foraging is to be accepted as a responsible urban activity, it’s vital that everyone involved doesn’t overdo it. I’m not offering a lecture; I just wanted to mention it.
Pregnancy
As a general rule of thumb, it’s unwise to try anything new if you are pregnant, in case of any adverse effects on you or your baby. This applies even more so to wild food, some of which may contain chemical compounds that are fine when not pregnant but harmful if you are i.e. some pine needles can induce miscarriage in animals, some plants stimulate milk flow, numerous herbal remedies and pharmaceutical medicines are not recommended during pregnancy.
Dog poo and wee
The main danger to human health in dog faeces is the presence of the eggs of toxocara canis. This is a worm, which lives harmlessly in our furry friends but presents a danger to humans and can also spread by living in the soil long after the faeces have disappeared. Whether urban foraging or in the countryside, avoid dogs muck and wash anything you find at ground level. Dogs wee, due to clever canine leg cocking may be on plants a good bit higher so I never eat anything as I go along unless I’m sure its out of the dog wee zone (how high can a wolf hound pee anyway?), or unless its in an area I’m sure no dogs could access.
takenn directly from https://www.foragelondon.co.uk/sensible-foraging/