If a cancer patient refuses treatment in favour of cannabis, the person who advised them can also face legal risk. This part covers decisions made for children and what Thai law says about giving medical advice and making cannabis claims. It also covers what is safe to post on a forum and what doctors can do after a patient refuses treatment.
Part 1 made three points. A competent adult may refuse treatment. Studies show worse survival when people with curable cancers use alternative medicine instead of standard treatment. The measurable harm is linked to the refusal, not to using the remedy. The figures are in Cannabis and Cancer: What the Evidence Supports and What It Does Not.
This article is not medical advice and not legal advice. It does not recommend accepting or declining any treatment. It explains general legal principles and the position of anyone who gives advice. If you face this decision, talk to your oncology team (the doctors and nurses treating your cancer). For legal questions, talk to a qualified lawyer in your country.
This is Part 2. Part 1: When a Patient Declines Conventional Cancer Treatment in Favour of Cannabis: Autonomy, Outcomes, and Who Carries the Legal Risk
1. When the Patient Is a Child: General Principles Only
This article does not discuss any real case involving a child. Do not post details of a child’s case on a public forum. The posting rules are in the Community Guidelines. What follows covers general principles only.
Parents make decisions for their child, but their authority has limits. In most legal systems, decisions about a child’s medical care are judged by one standard: the best interests of the child. If a parent’s decision falls outside that standard, courts can authorise treatment even when the parents object.
The adult’s right to refuse, described in Part 1, does not extend this far. The parent is not the person whose life is at stake. In Thailand, the Declaration of Patient’s Rights and Duties says that parents or legal guardians use a patient’s rights for patients under 18.
Teenagers are a grey area in the law. Many countries accept that a minor who is mature enough may agree to treatment. Fewer countries apply the same rule to refusal. When a mature minor refuses life-saving treatment, the law often sets a higher bar, or lets a court override the refusal. The law here differs a lot between countries and is not settled.
Two practical points follow:
- A parent deciding for a child is not in the same legal position as an adult deciding for themselves. They should be told this plainly.
- Anyone who advises on a child’s cancer treatment is in the most legally exposed position described in this article.
What to do if you are a parent: before deciding, ask the treating team and a lawyer how the law applies to your child’s case. What to do if someone asks you for advice about a child’s cancer: do not advise. Encourage the parent to take every question, including about cannabis, to the child’s treating team.
2. Where the Person Giving Advice Stands
This section is for anyone who answers health questions online. It is the reason this article was written.
Giving treatment advice to an individual is regulated
Thailand’s Medical Profession Act B.E. 2525 defines “the medical profession” broadly. It includes examining, diagnosing, treating and preventing disease.
- Section 26: no one may practise medicine, or present themselves as ready to practise it, without a licence under the Act.
- Section 43: breaking this rule is punishable by up to three years in prison, a fine of up to 30,000 baht, or both. This is the penalty in force today.
- A draft amendment was put out for public comment in August 2026. It proposes raising the penalty to five years and 500,000 baht. It is not law.
The Act exempts certain people:
- people treating themselves;
- people helping a patient out of humanitarian duty, without payment (this does not cover surgery, radiation or injections);
- students working under supervision;
- authorised government and charity staff;
- certain practitioners licensed under other health laws, within the scope of their licence;
- authorised foreign experts.
Courts have not clearly decided whether an online post counts as practising medicine under Section 26. The highest risk comes from posts that diagnose a named person or tell them what to take.
Most people miss the phrase “or present themselves as ready to practise”. On its wording, nobody has to be harmed for it to apply. No money has to change hands either.
Cannabis advertising and health claims have separate rules
Under the Notification of the Ministry of Public Health Re: Controlled Herbs (Cannabis), B.E. 2568, cannabis flower is a controlled herb. The Notification was issued under the Thai Traditional Medicine Protection Act B.E. 2542 and has been in force since 26 June 2025. The main rules:
- Flower may only be sold against a prescription on form PT 33 (ภ.ท.33) from an authorised practitioner.
- Each prescription covers no more than 30 days.
- Advertising and online sale of flower are prohibited. What this means for forum posts is explained in Advertising and Selling Rules for Cannabis in Thailand: What You Can and Cannot Post on Asiannabis.
Press reports give different penalties for selling without a valid prescription. Check the Thai-language text in the Royal Gazette before relying on any figure.
Translator’s note: under Section 78 of the 1999 Act, selling a controlled herb without a licence (Section 46) is punishable by up to 1 year in prison, a fine of up to 20,000 baht, or both. The Act contains no “3 months / 25,000 baht” penalty, so do not rely on that figure if you see it.
Extracts with more than 0.2% THC are still Category 5 narcotics. Two Ministerial Regulations of B.E. 2569 tightened licensing in 2026. They are explained in Thailand’s Two Ministerial Regulations of B.E. 2569.
- The regulation on cannabis or hemp extracts came into force on 26 April 2026.
- The Controlled Herbs (No. 2) regulation, which tightens licence criteria for cannabis flower, came into force on 30 April 2026.
The PT 33 prescription rules come from the B.E. 2568 Notification described above.
Translator’s note: the draft Cannabis Control Act is not law yet. The Cabinet approved the draft on 22 September 2026 and sent it to the House. Until it passes, the rules above are the ones that apply. The draft is explained in The Draft Cannabis Control Act.
What this means for one post
Some posts make a health claim and also tell readers where to get the product. Such a post breaks more than one set of rules at once.
A post that plainly gives medical advice is still medical advice if you add “this is not medical advice” at the end. The disclaimer does not change what the post does.
The harm you will never hear about
There is also a moral risk that no law covers. Someone may decline curative treatment because of something you wrote. Nobody will tell you, and you will never find out. You cannot learn from that harm afterwards, so the only time to weigh it is before you post.
What to do before posting an answer to a health question: check whether your post tells a specific person what to take or what to stop. Also check whether it says where to get a product. If either is true, rewrite the post. Describe your own experience or link to the evidence instead.
Translator’s note: the Thai law above applies to posts made in Thailand and about Thailand. Other Southeast Asian countries have their own laws on medical practice and cannabis, and this article does not summarise them. If you post from another country, check your local law with a lawyer.
3. What to Post and What Not to Post
The binding rules are in the Community Guidelines. When health questions come up, this table shows general good practice:
| Fine to post | Not fine to post |
|---|---|
| Your own experience, described in the past tense, as yours | Telling another member what to take or what to stop |
| Links to published evidence, and a discussion of what it shows | Advising anyone to decline or delay treatment |
| What a prescriber told you | Diagnosing, staging or interpreting someone else’s test results |
| Encouraging someone to talk to their oncology team | Offering to supply anything to anyone |
| General discussion of laws and regulations | Presenting general information as advice for one person’s case |
Sometimes someone posts in great distress soon after a diagnosis. The useful reply is not a treatment plan. Acknowledge what they are going through. Then encourage them to take every question to the team treating them, including the question about cannabis.
For example: “I’m sorry you’re dealing with this. Please ask your oncologist directly about cannabis. They know your cancer, its stage and your other medicines.” This is not a way of brushing them off. Only the treating team can give an answer that accounts for their actual disease, stage and medicines.
What to do: save the table above. Check your next reply to a health question against it before you press “post”.
4. What a Doctor Can Do After a Refusal
A refusal does not end the relationship between doctor and patient. Symptom control, palliative care (care focused on comfort and quality of life) and regular check-ups are still available. Offer them clearly. Patients often assume that declining one treatment means losing all care.
The most important practical step is to ask what else the patient is taking. Ask without judging, and explain why you are asking. Patients hide what they take because they expect a negative reaction.
What stays hidden cannot be checked for interactions. These include interactions with:
- anticoagulants (blood-thinning medicines);
- immunotherapy;
- medicines broken down by the same liver enzymes as cannabinoids. How this works is explained in Cannabinoid Pharmacokinetics.
Hidden products also cannot be considered when a lab result comes back with no clear explanation. The forum topic Drug Interactions: The List to Take to Your Doctor helps patients prepare a full list.
Translator’s note: some patients do not count cannabis oil, herbal medicines or supplements as “medicine”. Ask about each one by name. In Thailand, legal cannabis flower comes only with a PT 33 prescription, so a patient may be reluctant to mention cannabis obtained another way. Telling them that the question is about their safety, not about reporting them, can make them more willing to answer.
What to do if you are a doctor: at every visit after a refusal, ask one question: “What are you taking now, including oils, herbs and supplements?” Write down the answer. You can then check for interactions and explain unexpected results.
Your experience can help other readers. Please share it below this topic.
- If you are a doctor in Thailand or elsewhere in the region and have had this conversation with a patient: what made it go better or worse?
- If you are a patient or carer who has faced this decision: what information did you most need at the time but not have?
Please do not post anything that could identify another person.
General information only. This is not medical advice and not legal advice. Legal provisions are summarised from published sources as of October 2026 and may change. Check current requirements with a qualified professional before relying on them.
Further reading on Asiannabis
- Why Personal Testimony Is Not Medical Evidence — and What It Is Good For Instead
- Drug Interactions: The List to Take to Your Doctor (linked in section 4 above)
References
- Medical Profession Act B.E. 2525 (1982), Sections 26 and 43 (Thailand).
- Notification of the Ministry of Public Health Re: Controlled Herbs (Cannabis), B.E. 2568, issued under the Thai Traditional Medicine Protection Act B.E. 2542; in force 26 June 2025.
- Thai Traditional Medicine Protection Act B.E. 2542 (1999), Sections 46 and 78.
- Ministerial Regulation on Cannabis or Hemp Extracts, B.E. 2569 (in force 26 April 2026).
- Ministerial Regulation on Controlled Herbs (No. 2), B.E. 2569 (in force 30 April 2026).
- Declaration of Patient’s Rights and Duties, Medical Council of Thailand and other health professional councils, 2015.