▁when ▁the ▁leaf ▁extract ▁was ▁added ▁to ▁cult ures . ▁Another ▁scientific ▁study ▁from ▁Japan ▁indicates ▁that ▁the ▁lab ▁r ats ▁that ▁a te ▁a ▁mixture ▁of ▁bet el ▁leaf ▁and ▁are ca ▁n uts ▁all ▁had ▁severe ▁thick ening ▁of ▁the ▁upper ▁dig est ive ▁tract , ▁whereas ▁after ▁under going ▁a ▁di et ▁of ▁bet el ▁leaves ▁alone , ▁only ▁one ▁labor atory ▁rat ▁ended ▁up ▁having ▁a ▁forest om ach ▁pap ill oma . ▁ ▁Bet el ▁leaf ▁extract ▁alone ▁has ▁not ▁been ▁shown ▁to ▁cause ▁significant ▁side ▁effects , ▁but ▁there ▁are ▁side ▁effects ▁associated ▁with ▁the ▁use ▁of ▁bet el ▁qu id . ▁ ▁Econom ics ▁ ▁Bet el ▁v ines ▁are ▁cultiv ated ▁throughout ▁sout heast ▁Asia ▁in ▁plots ▁whose ▁area ▁is ▁typically ▁ 2 0 ▁to ▁ 2 0 0 0 ▁square ▁metres ▁( 0 . 0 0 5 ▁to ▁ 0 . 5 ▁a cre ). ▁ ▁Malays ian ▁far mers ▁cultiv ate ▁four ▁types ▁of ▁bet el ▁plants : ▁si ri h ▁India , ▁si ri h ▁Mel ay u , ▁si ri h ▁C ina ▁and ▁si ri h ▁U d ang . ▁The ▁har vest ▁is ▁then ▁sold ▁in ▁bund les ▁of ▁ 1 0 ▁leaves , ▁each ▁bundle ▁cost ing ▁in ▁ 2 0 1 1 ▁between ▁MY R ▁ 0 . 3 0 ▁to ▁ 0 . 5 0 ▁($ 0 . 0 7 ▁to ▁$ 0 . 1 2 ▁per ▁bundle ). ▁ ▁In ▁Sri ▁L anka , ▁bet