Traditional medicine in India, China and Thailand used cannabis as weak, whole-plant preparations eaten in food. Modern cannabis products are far stronger and are mostly inhaled, so the old safety record does not carry over to them. This part compares each traditional claim with current evidence. It also explains why Thailand’s list of cannabis prescribers is unusual, and which contamination risks matter to patients and growers.
Part 1 covered what each tradition actually recorded. In short: Indian bhang made from leaves and seeds, Chinese medicine’s interest in the seed, and the Thai use of the leaf in cooking and medicine. For modern evidence, this article relies on two United States government bodies. The National Center for Complementary and Integrative Health (NCCIH) studies complementary and traditional medicine. The National Cancer Institute (NCI) is the US cancer research agency. Where a traditional claim conflicts with them, this article follows them.
This is Part 2. Part 1: Cannabis in Traditional Medicine: Ayurveda, Chinese Medicine, Thai Practice and What Modern Evidence Says
1. Weak Food Preparations Versus Strong Inhaled Products
What the Traditional Preparations Had in Common
Almost every traditional preparation shared three features:
- Whole plant, not an extract.
- Low potency (a low content of active compounds).
- Taken by mouth inside food. This means a slow onset and heavy first-pass processing. The gut and liver break down much of the drug before it reaches the bloodstream.
Modern products reverse all three. Cultivars grown for their effect range from about 2% to over 20% tetrahydrocannabinol (THC, the compound that causes the “high”). Industrial hemp, by contrast, is defined by a limit of roughly 0.3% THC. Extraction concentrates the compounds further, and most people today inhale cannabis or use concentrates.
Translator’s note: Thai rules on extracts draw the line at 0.2% THC, not 0.3% (see Thailand’s 0.2% and 1.0% THC lines). The Ministerial Regulation on Cannabis or Hemp Extracts B.E. 2569 has been in force since 26 April 2026. Under it, a licence for extracts above 0.2% THC can go only to three kinds of holder. They are Thai juristic persons that are not “foreign” under the Foreign Business Act B.E. 2542, state agencies, and the Thai Red Cross Society.
Why the Old Safety Record Does Not Carry Over
A tradition’s safety record covers one material used in one way. Raise the potency about tenfold and change how it is taken, and you are no longer testing the same treatment.
Extraction also concentrates whatever else was on the plant. Many pesticides are lipophilic, meaning they dissolve in fats and oils. So they dissolve into the same solvents that pull out the cannabinoids.
Montoya and colleagues published a review on this in 2020 in the journal Frontiers in Pharmacology. The review cites research showing that 69% of pesticides used in cultivation survive into the smoke. It also reports that the lungs absorb mercury about ten times more efficiently than the gut.
What you can do: before you accept “traditional use” as proof of safety, compare your product with the traditional one. Ask whether it is an extract, how strong it is, and whether it is inhaled. If any answer is different, the tradition tells you nothing about your product’s safety.
Translator’s note for growers: if your flower goes to extraction, any pesticide residue on it ends up concentrated in the extract. Use only pesticides registered with the Department of Agriculture (กรมวิชาการเกษตร), exactly as the label says. See what you may legally spray on cannabis. Record each spray with product, date and dose, so you can show a buyer or auditor what the crop received.
2. Traditional Claims Against Modern Evidence
The table below names some classical sources. The Sushruta Samhita is a founding Ayurvedic medical text from roughly the 2nd–5th centuries CE. The Atharvaveda is an ancient Hindu religious text from around 1500–1000 BCE.
Where a tradition and the two US government bodies disagree, this article follows the government position.
| Traditional claim | Tradition | What current evidence shows |
|---|---|---|
| Increases appetite | Indian | Partial overlap. A synthetic (lab-made) THC medicine is approved for appetite loss in people with HIV (human immunodeficiency virus). |
| Relieves nausea and vomiting | Not a main claim in the classical texts | Closest to supported. Cannabinoids beat placebo and matched other medicines for nausea caused by chemotherapy. |
| Relieves pain | Indian; Thai use as a muscle relaxant | Weak. A 2018 review found a small benefit: 29% of users reached a 30% reduction in pain, against 26% on placebo (dummy treatment). See chronic pain. |
| Relieves anxiety; helps sleep | Atharvaveda; Indian use as a sleeping aid | Thin. A little evidence suggests cannabinoids might ease anxiety. People report better sleep, but cannabis may not be the cause. |
| Treats diarrhoea and dysentery | Sushruta Samhita | Conflict. Cannabis did no better than placebo at bringing remission (a period free of symptoms) in inflammatory bowel disease, a long-term inflammation of the gut. The effect is unknown for irritable bowel syndrome, which is recurring gut pain without visible inflammation. |
| Fever, sunstroke, phlegm, speech problems, aphrodisiac | Indian | No body of modern evidence exists. |
| Eases labour pains | Thai | No support. Use in pregnancy carries known risk, including lower birth weight after smoking. |
| Treats or cures cancer | Modern folk claim, not classical | Rejected. The US Food and Drug Administration (FDA), the US medicines regulator, has not approved cannabis for cancer or for any other condition. Findings that cannabis fights tumours come from laboratory and animal studies, not from adequate human trials. |
Where the Evidence Agrees, Disagrees or Is Missing
The overlap is narrow, and it is about symptoms: nausea, appetite and, weakly, pain. The best-supported modern use matches nothing in the traditional record. That use is a purified cannabidiol (CBD) medicine. In the United States it is approved for seizures in Lennox-Gastaut syndrome and Dravet syndrome, two severe childhood epilepsies, and in tuberous sclerosis complex, a genetic disorder. The traditions never found this use.
The clearest conflict is in the gut. Some long-term, high-dose users develop cannabinoid hyperemesis syndrome, which means repeated bouts of severe vomiting. This goes against cannabis’s reputation as a plant that stops nausea.
For the other claims, nobody has run the studies. A missing study does not disprove a claim. But it does not give you permission to use cannabis for that purpose either.
What you can do: before using cannabis for any symptom in this table, read the forum topic on that condition. Then take the drug-interaction list to your doctor and check it against your other medicines.
3. Thailand: From Prohibition to Traditional-Medicine Prescribers
From Ban to Delisting to Controlled Herb
Thailand banned cannabis under the Cannabis Act B.E. 2477 (1934–35). The Narcotics Act B.E. 2522 (1979) strengthened the ban. In 2018 Thailand became the first country in Southeast Asia to legalise medical cannabis.
In June 2022, the cannabis plant was removed from the narcotics list, and more than 3,000 people jailed only for cannabis offences were released. By 2025, many thousands of cannabis shops had been licensed.
Then the rules tightened again. The Notification of the Ministry of Public Health Re: Controlled Herbs (Cannabis), B.E. 2568 took effect on 26 June 2025. It was issued under the Thai Traditional Medicine Protection Act B.E. 2542 (1999). It made cannabis flower a controlled herb for medical use only.
Flower may be sold only with a PT 33 (ภ.ท.33) prescription. The prescription:
- must be on the official PT 33 form;
- must carry the name and licence number of a prescriber from one of the seven professions listed below;
- cannot cover more than 30 days.
Sellers may supply flower only against such a prescription. The Department of Thai Traditional and Alternative Medicine oversees this system. This department is the part of the Ministry of Public Health that oversees Thai traditional medicine. In 2026 the Ministry worked with the police against fake PT 33 forms. Advertising and online sale of cannabis flower are prohibited.
Seven Kinds of Prescriber
Seven groups of practitioners may prescribe cannabis:
- medical doctors;
- Thai traditional medicine doctors;
- applied Thai traditional medicine doctors (a separately licensed branch);
- folk healers;
- Chinese medicine practitioners;
- pharmacists;
- dentists.
Why This Arrangement Is Unusual
Most countries let only conventional doctors prescribe medical cannabis. Thailand runs it through a traditional-medicine department, and folk healers are legal prescribers. This is the same system that was outlawed as quackery a century earlier.
This has two effects. First, it gave Thailand a ready licensed workforce, and a legitimacy that a purely pharmaceutical system would have lacked. Second, part of the power to prescribe now sits with practitioners whose reasoning is not based on evidence. That is a legal fact about who may prescribe, not a judgement about who is right.
Translator’s note: the rules for licence holders tightened further in 2026. The Ministerial Regulation on Controlled Herbs (No. 2) B.E. 2569 tightens the criteria for cannabis flower licences. It took effect on 30 April 2026, the day it was published in the Royal Gazette.
Under Section 78 of the 1999 Act, two offences carry up to 1 year in prison and/or a fine of up to 20,000 baht. One is selling or processing a controlled herb without a licence. The other is continuing business while a licence is suspended.
The draft Cannabis Control Act is not law yet. The Cabinet approved the draft on 22 September 2026 and sent it to the House. For details, see Thailand’s two 2026 regulations and licensing, suspension and penalties.
What you can do: when you get a PT 33, check three things. It should be on the official PT 33 form, show the prescriber’s name and licence number, and cover no more than 30 days. If a seller offers flower without a prescription, or online, do not buy, because both break the rules.
4. Safety in Practice
Labels Often Do Not Match the Contents
Traditional preparations have no defined content. Modern products often have none either. In a 2017 study, 69% of 84 CBD products bought from 31 online retailers were wrongly labelled.
The NCCIH warns that such products may contain more or less CBD than the label states. They may also contain contaminants, including THC.
Pesticides, Heavy Metals and Mould
The 2020 review by Montoya and colleagues documents three kinds of contamination:
- Pesticide residues were found in 84% of samples in one Washington State study and in 49% of samples in one California study. See pesticide residues on cannabis.
- Heavy metals: cannabis is a hyperaccumulator of cadmium, lead and mercury, meaning it takes up and stores far more of them than most plants. This is why it has been studied as a way to clean polluted soil. See contaminant remediation.
- Fungi and bacteria, including Aspergillus and Fusarium species. These are mainly dangerous to people with a weakened immune system, who are the people most likely to look for a medical product.
This problem is not unique to cannabis. A 2008 study found that roughly 20% of the Ayurvedic remedies it examined contained lead, mercury or arsenic.
Translator’s note for growers in Thailand and Southeast Asia:
- Mould: in the rainy season, high outdoor humidity and drying rooms at 30–35 °C favour moulds such as Aspergillus on drying flower. See mycotoxins and the rainy-season risk.
- Power cuts: a power cut stops fans and dehumidifiers. Keep a hygrometer (humidity meter) in the drying room and log it morning and evening. That way you notice a failure before mould sets in. See drying cannabis at 85–95% ambient humidity.
- Heavy metals: cannabis pulls cadmium, lead and mercury out of the soil. Before planting a medical crop on a new plot, have the soil and irrigation water tested. The result tells you whether that plot can produce flower that passes a heavy-metal test.
- Testing each batch: before supplying a clinic or licensed shop, have the batch tested for pesticides, heavy metals and microbes, and keep the certificate of analysis. To find a laboratory, ask other members in the B2B Services section.
Interactions and Risks for Different Groups
CBD has been linked to interactions with other drugs. The NCCIH also lists these risks:
- a higher risk of road crashes;
- lower birth weight when the mother smoked cannabis during pregnancy;
- a higher risk of schizophrenia and other psychoses with frequent use;
- cannabis use disorder, meaning use the person cannot control despite harm. Adolescents are four to seven times more likely than adults to develop it.
Traditional remedies have also been found secretly mixed with undeclared pharmaceutical drugs. Many so-called natural remedies work only because they contain hidden conventional medicines.
What you can do: tell your doctor or practitioner about every medicine, herb and supplement you take, so interactions can be checked. Do not drive after using cannabis. If you are pregnant or a teenager, read the contraindications topic and talk to a doctor before any use.
5. How to Read a Traditional Claim Responsibly
Ask what the text actually says, when it was written, and whether the date or author is disputed. Notice when a claim rests on a single encyclopaedia entry. Notice too when a Sanskrit, Chinese or Thai term is translated loosely.
Traditional systems suggest ideas worth testing, and clinical trials test them. When the two disagree, the health authority is the better guide to what will happen in your body. Saying so is not disrespect for the tradition.
What you can do:
- Work with a licensed practitioner. In Thailand, that may legally be a traditional practitioner under the 2025 rules. The licence shows the practitioner is allowed to prescribe.
- Tell the practitioner everything you take, so interactions can be checked.
- Choose tested, certified material, and do not trust labels alone. Ask for the certificate of analysis to see what the product actually contains.
- Treat any claim that cannabis treats or cures a disease as a warning sign about the source. No regulator has approved cannabis to cure a disease.
Join the Discussion
Post your experience below this topic:
- In Thailand: has a Thai traditional medicine doctor or a folk healer prescribed you cannabis under the 2025 rules? What did the consultation look like?
- Growers: what tests or records do clinics and licensed shops ask you for before they accept a batch?
- In India: is bhang treated as medicine, as a festival custom, or both? Does anyone still cite the classical texts?
- Chinese medicine practitioners, in China or Thailand: do the practitioners you know use the seed?
- Named traditional formulas: if you can source a named traditional formula that this article left out, post it with the reference. A correction with a source is better than repeating folklore.
This article is part of the Asiannabis Community educational series on medical cannabis. It is general information, not medical advice. Treatment decisions belong with a licensed practitioner. The content is for education in places where medical cannabis is legally permitted.
References
- National Center for Complementary and Integrative Health (NCCIH). “Cannabis (Marijuana) and Cannabinoids: What You Need To Know”. Last updated November 2019.
- National Cancer Institute (NCI). “Cannabis and Cannabinoids (PDQ®)–Patient Version”. Last updated 15 August 2023.
- Montoya Z, Conroy M, Vanden Heuvel BD, Pauli CS, Park S-H. Cannabis Contaminants Limit Pharmacological Use of Cannabidiol. Frontiers in Pharmacology 2020;11:571832. doi:10.3389/fphar.2020.571832.
- Stockings E, et al. Cannabis and cannabinoids for the treatment of people with chronic non-cancer pain conditions: a systematic review and meta-analysis of controlled and observational studies. Pain 2018;159(10):1932–1954.
- Bonn-Miller MO, et al. Labeling Accuracy of Cannabidiol Extracts Sold Online. JAMA 2017;318(17):1708–1709.
- Saper RB, et al. Lead, mercury, and arsenic in US- and Indian-manufactured Ayurvedic medicines sold via the Internet. JAMA 2008;300(8):915–923.
- English Wikipedia entries “Cannabis in India”, “Cannabis in China” and “Cannabis in Thailand” (general summaries used for history). The Thai timeline figures were checked against news reports.
- Notification of the Ministry of Public Health Re: Controlled Herbs (Cannabis), B.E. 2568 (2025); Thai Traditional Medicine Protection Act B.E. 2542 (1999).
- Ministerial Regulation on Cannabis or Hemp Extracts B.E. 2569 (2026); Ministerial Regulation on Controlled Herbs (No. 2) B.E. 2569 (2026).