The plant is poisonous.
Application
The tobacco plant came to Europe with the Spanish around 1560. Initially, tobacco was used against intestinal worms and lice. Later, the well-known use of tobacco as a recreational drug was added.
Tobacco leaf extract can be used to control aphids.
Ingredients
All parts of the plant contain nicotine. The nicotine content is highest in the leaves and lowest in the flowers.

Nicotiana tabacum L. Photo from page in Joachim Burser's herbarium.