Scopolamine and hyoscyamine...
...are apparently just two of the toxins to be found in Deadly Nightshade, the North Downs very own package of poison. Although the roots carry the most potent doses, the whole plant is pretty noxious and you would be a fool to pick, chew, lick or digest any of it. And if you do, while you're at it, why not find a gang of adders to cosy up to just to increase the risk of hospitalisation.
I remember looking at Hemlock growing at Malden Rushett and thinking, "this stuff killed Socrates" nearly 3000 years ago. Laburnum is another common, yet highly toxic plant. Yew isn't too good for you either, not unless you're a Hawfinch, that is.