BANGKOK -- Thailand's general election in March had a potentially powerful side effect: It made a party that advocates the full legalization of marijuana the country's fifth-largest political force.

In a region that maintains some of the harshest narcotics laws on the planet, including death for trafficking, the cannabis taboo is beginning to go up in smoke. Even before the election, Thailand's junta became the first Southeast Asian government to legalize the drug for medicine and research, amending a strict 1979 law as a "New Year's gift" to the people after heavy lobbying by pro-cannabis groups.

But as Asian countries slowly begin to follow the lead of Western governments that have accepted weed for medical and even recreational use, critics warn the authorities may not fully understand the consequences as they zero in on a new source of tax revenue.

Thailand's Bhumjaithai party argues fully legal pot would bring big economic benefits. In the election campaign, it vowed to promote cannabis as a lucrative commodity that could help poor farmers earn up to 400,000 to 600,000 baht ($13,000 to $19,500) a year. Now the party is a member of Prime Minister Prayuth Chan-ocha's coalition government, and has been rumored to have a shot at the health ministry portfolio.

Supachai Jaisamuth, a leading member of the party, said it will continue to push for embracing cannabis as a cash crop. "We are now a government coalition party so it is easier to continue the policy that we promised the Thai people during the election," he said.

For the time being, patients that meet certain conditions are eligible for marijuana prescriptions. After Thailand's king approved the legal revision in February, the government held a 90-day amnesty program under which people in illegal possession of the drug could register to verify that they legitimately need it, with no risk of punishment. The Bangkok Post reported that 1 in 10 applicants, out of about 20,000, were deemed to have valid needs, such as cancer sufferers.

So far, only the Government Pharmaceutical Organization can legally grow cannabis and the extract cannabidiol, known as CBD, for medical products. The GPO has set up the nation's first indoor farm to develop Thailand's own patented cannabis medicines, said Vichien Keeratinijakal, an agronomy lecturer at Kasetsart University who conducted a cannabis extract project for the organization.

"The first lot of 2,500 bottles of CBD extract with 5 cc each will be distributed to hospitals and medical schools across the country by July-August, to be used in medical trials, particularly as a pain-control drug," Vichien said, adding it would also be used as a sublingual drop for epilepsy patients.

The authorities will consider applications from certain types of organizations and health care practitioners that wish to grow, import or export medical marijuana. Unauthorized possession remains punishable by up to 15 years in prison.

Proponents of legalization see enormous untapped business potential. Prohibition Partners, a nongovernmental organization founded two years ago with a mission to open up the international cannabis industry, estimates 85.5 million of Asia's roughly 4.5 billion population in 2019 are cannabis users. The group projects the Asian market will be worth $8.5 billion in 2024, with medical use accounting for $5.8 billion of that.

Eager to tap the market, cannabis producers and large pharmaceutical companies from the West hope to see more moves toward legalization in Asia. Allowing medical cannabis is seen as a step toward greenlighting recreational use, which is exactly what happened in Canada -- which legalized cannabis in late 2018 after years of allowing patients to use it.

There are rumblings of change in Asia beyond Thailand. South Korea's National Assembly legalized cannabis for medial purposes in November. The decision came in response to a patients group that urged parliament to lift the ban on marijuana to help people afflicted with rare diseases. As in Thailand, the change was a major step in a country that maintains strict laws on the drug -- and even warns it will prosecute citizens who try it in other countries where it is legal.

South Korea still imposes tight controls on medical use -- issuing only case-by-case approvals. But after the legalization, imports of some pharmaceutical products made with cannabis became possible in March.

Activists say the country should allow wider use of medical marijuana. In a statement, the Organization of Legalizing Medical Cannabis in Korea demanded the government allow patients to obtain "prescriptions for marijuana without any inconvenience and limitations."

"There should be ways for patients to use a wide range of medical marijuana for quick and smooth treatments."

In Malaysia, a death sentence handed down last year to man who sold cannabis oil to patients stirred so much controversy that Prime Minister Mahathir Mohamad called for a review of the case. Some expect Malaysia may soon follow Thailand in legalizing medical marijuana, though an official with the Health Ministry's Pharmaceutical Services Programme said no official studies are currently looking into that possibility.

Still, the official said Malaysia has no objection to the use of cannabis as long as it is in the form of a registered product -- not raw weed. "The cultivation of cannabis for medical use is [also] still prohibited."

Some experts urge an abundance of caution, noting the benefits and side effects of marijuana are not well-understood especially in Asian societies.

A 2017 report issued by the National Academies of Sciences, Engineering and Medicine in the U.S. found that patients "treated with cannabis or cannabinoids [the plant's chemical compounds] were more likely to experience a significant reduction in pain symptoms." It also cited evidence that the drug can help to alleviate multiple sclerosis-related muscle spasms as well as nausea and vomiting in cancer patients undergoing chemotherapy.

Yet, even after legalization, Thai cancer specialist Dr. Virote Sriuranpong declines to prescribe cannabis to his patients.

Among the concerns are unsubstantiated claims that cannabis and its derivatives can actually cure cancer. The U.S. National Cancer Center warns on its website that such products "are being illegally promoted as potential cancer cures. These oils have not been evaluated in any clinical trials for anticancer activity or safety."

"I don't want to put the lives of my patients at risk," Virote said, stressing it will take years to determine whether cannabis can do anything more than make cancer more bearable. "At the same time, we already have efficient drugs to help kill pain in several cases of cancers," added the doctor, who is also the former president of the Thai Society of Clinical Oncology.

Some Thais may be taking a dangerous risk by taking cannabis extract improperly, including products from profiteers who use substandard methods of extracting CBD. Illegal oils have turned up on Facebook, Instagram and various websites, posing a danger to patients who do not understand the potential hazards.

A young Thai girl who declined to give her name told the Nikkei Asian Review that she traveled more than 100 km from her hometown in the western province of Kanchanaburi to Suphanburi, in the center of the country, to obtain 20 capsules containing cannabidiol. She was one of thousands of patients who lined up to get the capsules from an organization that bills itself as a foundation that helps poor patients access efficient and affordable cancer killers.

"Many of the patients, mostly those who have cancer, were brought back to the hospital with serious conditions because they used CBD oil incorrectly," Virote said. "That could bring deadly results."

The Bhumjaithai party's cannabis advocacy helped it become Thailand's fourth-largest political force in the March election. © Reuters

Another common argument is that legalizing medical marijuana can create a slippery slope toward casual use and possibly serve as a "gateway" to more serious drugs.

The United Nations-backed International Narcotics Control Board issued a report in March warning that poorly regulated medical cannabis programs would spark an increase in recreational use while diminishing public concern over the drug's harmful effects.

Shinji Funayama, professor at Nihon Pharmaceutical University in Japan, said, "Once cannabis medication for painkilling and other purposes is approved, this may lead to reduced control over the use of more addictive drugs like stimulants."

Nevertheless, such concerns have not stopped a number of individual U.S. states from legalizing the drug for medical treatment and some for recreational use. It may be only a matter of time until more Asian governments follow suit.

In the Philippines -- where President Rodrigo Duterte has waged a deadly war on drugs -- a bill seeking to legalize marijuana was reintroduced on July 1, the first working day for a new congress.

Representative Antonio "Tonypet" Albano revived the proposal, called the Philippine Compassionate Medical Cannabis Act, which his brother had first introduced in the previous congressional session. The bill was approved by the House of Representatives in January but failed to secure a sponsor among the senators.

"I do not intend to legalize" marijuana, Duterte said in March. But even the fiercely anti-drug president said in December 2018 that he took marijuana to stay awake amid his busy schedule, though he later insisted it was just a joke.

Albano told the Nikkei Asian Review that more safeguards have been put in place to prevent abuse and said he is holding out hope that Duterte will reconsider.

"That is my belief that the president's ears can be opened, can be subject to change," Albano said, "especially if he sees that this is really for the benefit of the Filipino people."

Nikkei staff writers Mikhail Flores in Manila, Kim Jaewon in Seoul and P Prem Kumar in Kuala Lumpur contributed to this article.