Betel nut (Areca catechu). Betal nut is indigenous to the Malay 
Peninsula. The Malayan state of Penang is named after the plant 
(Pinang in Malay). The betel nut contains a stimulant, arecoline, 
an alkaloid which affects the nervous system similar to the action 
of acetylcholine. The arecoline effect is highly complex and 
includes constriction of the pupil, decreased heart output,
stimulation of various glands, and vasodilation. The effect is 
described by some as similar to nicotine and to other was like 
"way too much coffee." Topical arecoline causes a considerable 
smarting of the eye and induces a strong miosis like pilocarpine. 
The miosis occurs within 5 minutes reaching its maximum at 30 
minutes and the pupil returns to normal in 90 minutes. The 
intraocular pressure drops due to increased aqueous outflow 
through the trabecular meshwork.