The poisonous substances in some plants are valuable in medicine when properly used.
The common Foxglove (a tall poisonous plant that has pink or white bell-shaped flowers all the way to the stem) is a herbaceous plant grown for its colourful flowers.
It also contains digitalis, a substance which if taken in large doses, can cause death. But in the correct dosage, it is used as medicine to regulate heartbeat.
In the tuber family, there are plants which are important to our diet, like potatoes and many others but some tubers are also poisonous.
Almost all contain a poison called solanine in the leaves and unripe fruit. The Petunia and the Tobacco Plant are also part of this family.
Credit : The Big Book of Knowledge.