The drug, marketed as Tabex, is currently only available in Eastern Europe. Smokers usually take the pill for three or four weeks.
New research suggests it can triple a smoker's chances of staying off cigarettes after one year compared to those taking a placebo.
It is much less costly than nicotine patches or Chantix, a pill commonly prescribed in the U.S. Generic versions of the new drug cost $5 to $17 a month, compared to about $300 for a 12-week supply for Chantix.
The drug is made from laburnum seeds that contain a natural nicotine substitute. Researchers said the seed was discovered when much of the Soviet Union's drug research was farmed out to Bulgaria. Russian soldiers referred to it as "fake tobacco."
Soon, it will be available in developing countries including China and India, but experts are unsure whether it will ever make it to Western markets without larger trials and without a big pharmaceutical company stepping in to pay for them.
About 95 percent of smokers who try to quit without help fail within six months, and more than two-thirds of the world's 1 billion smokers live in developing countries. Smoking is the world's leading cause of preventable death.
The Associated Press contributed to this report.
