Question: what is the most dangerous plant

Dheeraj Rathore answered on 12 Nov 2019:

Dangerous plants can cause blisters, irritation to skin, tummy upset if consumed or even worse.
Poisonous plants are mostly dangerous. The poisonous plants that are found in Ireland include monkshood and laburnum, to hemlock, aquilegia, autumn crocus (colchicum autumnale), lords-and-ladies and hellebores.

You can find the pictorial description in the Irish examiner article here:

https://www.irishexaminer.com/breakingnews/lifestyle/is-your-garden-toxic-5-of-the-most-common-plants-which-cause-blisters-tummy-upsets-and-worse-858701.html

In case of emergency:
We should be aware of the species of plants which are toxic and make others aware too.
If someone has ingested the toxic plant or plant parts, do seek medical attention from the accident and emergency department of your local hospital, taking a plant sample with you.