It is a stimulant of the central nervous system. Nicotine can produce dizziness, nausea, and hallucinations in excess, and is physiologically addicting. The main active ingredient is nicotine. It is most common in Southeast Asia, but also in Africa and other places where Asian people have migrated. Lime is often added to hydrolyze and activate the alkaloids in the Areca catechu seeds.
Copious salivation is produced.
With frequent use, the teeth eventually turn brown or red. This is a stimulant permitted by Islam. Khat is one of the major cash crops of Ethiopia and is flown fresh daily to Yemen, and several other countries. Abuse of the plant is particularly bad in Yemen. Saudi Arabia has made khat illegal.