Media playback is unsupported on your device Media caption Cindy Sui reports from Taiwan on the moves to end betel nut use 
 
 It is used by almost a tenth of the world's population. It gives people a buzz equivalent to six cups of coffee and is used variously as a symbol of love, marriage and a cure for indigestion and impotence. 
 
 But it is also leading tens of thousands to an early grave. 
 
 The culprit? The humble betel nut. 
 
 Found across Asia, these nuts are harvested from the Areca palm and are chewed for their warming glow and stimulating properties. 
 
 Such is its effectiveness, that alongside nicotine, alcohol and caffeine, betel nuts are believed to be one of the most popular mind-altering substances in the world. 
 
 Although used by women and children, the nuts are especially popular among working-age men, who chew to stay awake through long hours of driving, fishing or working on construction sites. 
 
 But the short-lived benefits come at a terrible cost. 
 
 High rates of oral cancer are destroying the lives of many who buy betel nuts, often decades after their first taste. 
 
 Now in Taiwan, where the nuts are affectionately known as 'Taiwan's chewing gum', the government is taking action to curb this centuries-old habit and reduce the thousands of lives lost each year. 
 
 Dangerous combination 
 
 Image copyright Science Photo Library Image caption Regular betel nut chewers stand out from the crowd with their red-stained lips and teeth 
 
 The betel nut is a key part of many Asian cultures and can be consumed dried, fresh or wrapped up in a package known as a quid. 
 
 Although the exact preparation varies across countries and cultures, the quid is usually a mixture of slaked lime, a betel leaf and flavourings such as cardamom, cinnamon and tobacco. 
 
 Worryingly, the International Agency for Research on Cancer lists each ingredient, with the exception of cardamom and cinnamon, as a known carcinogen - or cancer-causing agent. 
 
 The slaked lime is seen as a particular problem as it causes hundreds of tiny abrasions to form in the mouth. This is thought to be a possible entry point for many of the cancer-causing chemicals. 
 
 "About half of the men here still don't know that betel nuts can cause oral cancer," says Prof Hahn Liang-jiunn, an oral cancer specialist at the National Taiwan University Hospital. 
 
 "[This is despite] Taiwan's incidence or mortality rates for oral cancer ranking among the top two or three in the world." 
 
 'I started chewing because everyone else did' 
 
 Image caption Qui Zhen-huang now warns others about the dangers of betel nuts. 
 
 Like most people, Qiu Zhen-huang, 54, was completely unaware of the risks. 
 
 A former gravel company worker, he chewed for ten years. Twenty years after quitting, he developed the disease. 
 
 "I started chewing betel nut because everyone at work did it," says Mr Qiu. 
 
 "We shared it with each other to build good relations." 
 
 Three years ago, a small hole developed in his left cheek and in just three months, the tumour grew to the size of a golf ball and completely changed his life. 
 
 "Whatever I ate flowed out. I had a gauze pad over it. It hurt," he said. 
 
 "It affected me a lot. I was so ashamed I avoided going out." 
 
 Each year, 5,400 Taiwanese men like Mr Qiu are diagnosed with oral cancer or pre-cancerous lesions and an estimated 80 to 90% of those also chew betel nuts. 
 
 An early symptom includes white or red lesions inside the mouth, but this can rapidly progress to grotesque flesh-eating tumours. 
 
 Unlike other cancers, these are difficult to hide, leaving sufferers physically and psychologically devastated. 
 
 "It's miserable for them," says Prof Hahn. 
 
 "Sometimes, even after surgery, they still can't perform basic functions, including expressing emotions through their face because the lower jaw also has to be cut depending on the scale of the cancer." 
 
 Tackling the scourge 
 
 Image caption The Taiwanese government is offering subsidies in return for cutting down betel nut palms 
 
 Luckily for Qiu Zhen-huang, his cancer was treated and his cheek reconstructed. 
 
 But the Taiwanese government is helping people detect the disease more quickly by providing around one million free screenings and funding programs to help people quit betel nuts for good. 
 
 In 2013, these measures helped cut the usage rate among men by nearly half. 
 
 Critics argue that action should have been taken much sooner as the cancer risk of betel nuts has been known since 2003. 
 
 However, pressure from those working in the industry has provided strong opposition to change. 
 
 Now the government is trying to reduce the domestic supply of betel nuts by offering subsidies to farmers to cut down their trees and plant alternative crops. 
 
 Other countries such as India and Thailand have also launched campaigns to discourage betel nut chewing. 
 
 But there is still a way to go. At a recent presentation to elementary school children of fishing industry workers, nearly all raised their hands when asked whether their parents or relatives chewed betel nuts. 
 
 And as the cancer can take up to 20 years to appear, the current changes will have come too late for many people - a fact that Mr Qiu keeps close to his heart. 
 
 "I'm one of the luckier ones." ||||| BBC has reported on the dangerous affliction hitting Taiwan—the chewing of Betel Nuts, which is believed to be responsible for its oral-cancer epidemic. 
 
 The deadly habit has been around for centuries in Taiwan, and is especially popular with blue-collar workers for its stimulating effect—the tiny nut gives the same buzz as six cups of coffee. 
 
 The Taiwanese government is now seeking to curb the prevalence of the Betel Nut due to its dangerous side-effects. Consumers of the nut are easily spotted by their red-stained lips and teeth, but it is the link between Betel Nut chewing and serious illness which is more worrying than the vampire-like appearance it causes. 80 to 90 percent of the 5,400 men who are diagnosed with oral cancer or lesions in Taiwan admit to chewing Betel Nuts. It is highly likely the custom of chewing Betel Nuts (also regarded as a cure for indigestion and impotence) has contributed to Taiwan ranking in the world's top three for incidence of and mortality rate from oral cancer. 
 
 The innocuous looking nut is harvested from the Areca palm and can be eaten dried, fresh, or in a 'quid'—wrapped up in Betel leaf and mixed with slaked lime, cardamom, cinnamon and tobacco. Indeed, it is this combination which exacerbates the danger, since all of these ingredients are also known cancer-causing carcinogens. 
 
 The Taiwanese government has responded by providing free programs aimed at convincing people to quit Betel Nuts, as well as offering incentives to Betel Nut farmers to cut down their Betel palms and grow other crops. However, Betel Buts still remain legal. 
 
 This is not the first time a popular snack has been found to cause cancer in Taiwan: millions of packets of contaminated dried fruit and fruit juice were recalled in 2011 once it was revealed they could cause cancer as well as liver and kidney damage. 
 
 Disconcertingly-high rates of cancer have also been reported on mainland China, with a 2014 survey revealing that one in 60 Shanghai residents had been diagnosed with cancer. ||||| What is betel nut? A deep red or purple smile is a common sight in many parts of Asia and the Pacific. But what’s behind it? This red residue is the telltale sign of the betel nut, which is chewed by millions of people across the globe. In its most basic form, betel nut is a seed of the Areca catechu, a type of palm tree. It’s commonly chewed after being ground up or sliced and wrapped in leaves of the Piper betle vine that have been coated with lime. This is known as a betel quid. Tobacco or flavorful spices may also be added. 
 
 History of a habit Betel nut has a long history in South and Southeast Asia and the Pacific Basin. In Guam and other Pacific islands, its use can be traced back as far as 2,000 years. A habit passed down through generations, chewing betel nut is a time-honored custom for 10–20 percent of the world’s population. Today, the World Health Organization (WHO) estimates that around 600 million people use some form of betel nut. It is one of the most popular psychoactive substances in the world, in fourth place after nicotine, alcohol, and caffeine. But while betel nut is an important cultural and social tradition in many countries, growing evidence points to serious health effects from regular use. 
 
 A burst of energy Many people chew betel nut for the energy boost it produces. This is likely due to the nut’s natural alkaloids, which release adrenaline. It may also result in feelings of euphoria and well-being. Some traditional beliefs hold that it may offer relief for a range of ailments, from dry mouth to digestive problems. However, the drug has not been well tested in clinical trials, and evidence of any health benefits is limited. According to one study published in the journal Cancer Prevention Research, betel nut has cancer-fighting properties. An Indian study suggests it may help with cardiovascular and digestive issues and have anti-inflammatory and wound-healing properties. However, a study in the South East Asia Journal of Cancer points to the lack of follow-up studies. It also says that more research is needed to confirm any of the betel nut’s benefits. A medical review of the nut’s effects published in the Indian Journal of Medical and Paediatric Oncology concludes that it’s an addictive substance with many more harmful effects than benefits. 
 
 Oral cancer and other dangers Research has revealed some serious health risks of betel nut. The WHO classifies betel nut as a carcinogen. Many studies have shown a convincing link between betel nut use and cancer of the mouth and esophagus. A study in the Journal of the American Dental Association reports that betel nut users are at a higher risk for oral submucous fibrosis. This incurable condition can cause stiffness in the mouth and eventually the loss of jaw movement. Regular chewing of betel nut can also cause gum irritation and tooth decay. Teeth may become permanently stained deep red or even black. An early study published in the American Society for Clinical Nutrition found a strong connection between betel nut and an increased risk of cardiovascular disease, metabolic syndrome, and obesity. Betel nut may interact with other drugs or herbal supplements. It could cause toxic reactions in the body or reduce the effects of medications. More testing is needed to determine just how betel nut affects other drugs. Regular betel nut use may also lead to dependency and withdrawal symptoms. The U.S. Food and Drug Administration (FDA) does not consider betel nut safe for chewing or eating. It has placed the nut on its Poisonous Plants Database. A fact sheet on betel nut with tobacco issued by the Centers for Disease Control and Prevention (CDC) warns of the following medical conditions associated with betel nut use with tobacco: oral submucous fibrosis 
 
 oral cancer 
 
 addiction 
 
 reproductive issues, including low birth weight in newborns 
 
 Raising awareness Health organizations and governments around the globe are taking steps to increase awareness of betel nut risks. Taiwan has declared an annual “Betel Nut Prevention Day.” City officials in Taipei now fine anyone seen spitting betel nut juice and require them to attend withdrawal classes. In 2012, the WHO released an action plan designed to reduce betel nut use in the Western Pacific. It calls for a combination of the following measures to curb the practice: policy 
 
 public awareness campaigns 
 
 community outreach
– Nicotine. Caffeine. Betel nuts. You may never have heard of them, but nuts from the Areca palm are hugely popular as a chewable stimulant: Almost a tenth of the global population enjoys them, the BBC reports. A millennia-old tradition, they're the world's fourth-most-popular psychoactive substance, Healthline adds. Their effect is similar to that of drinking six cups of coffee, and many workers engaged in lengthy physical tasks chew them to maintain alertness. Trouble is, they're incredibly dangerous. Potentially leading to oral cancer and terrible mouth lesions, they're likely responsible for tens of thousands of early deaths, the BBC notes. In Taiwan, about 5,400 men receive oral cancer diagnoses each year; as many as 90% of them are betel nut chewers. The situation is only made worse by the way betel nuts are often packaged: in what are called quids, which can be made using known carcinogens like tobacco and slaked lime. The latter can generate small abrasions in the mouth that may help the carcinogens get into the body. Despite the dangers, betel nuts are called "Taiwan's chewing gum," and about half the country's men aren't aware of the cancer issue, an expert says—even as people like Qiu Zhen-huang develop holes in their cheeks. Decades after he quit the stuff, he ended up with a golf ball-sized tumor. The FDA doesn't consider betel nuts safe, Healthline notes, and in recent years, Taiwan has been fighting their use—though it remains legal, Shanghaiist reports. Free screenings and other programs helped cut men's chewing rates in half two years ago, the BBC notes. (As for smoking: Keep doing it, and there's a 67% chance you'll die from it, a study finds.)