Wild mushrooms in Thailand's rainy season: why folk poison tests fail
Boiling with rice, a silver spoon or insect bites cannot spot a poisonous mushroom, and some toxins survive cooking. 2026 case counts, symptoms, and when to call 1669.
- Folk tests, boiling with rice, shallots or garlic, a silver spoon, or checking for insect bites, cannot confirm a mushroom is safe.
- The toxins in the deadly Amanita group survive heat. Thorough cooking does not remove them, and half a cap can kill.
- In 2026, Thailand's Health Region 9 recorded 335 mushroom poisoning cases and 1 death, mostly older adults.
- Nausea, vomiting, stomach pain or diarrhoea after eating mushrooms: call 1669 or go to hospital now, with any leftovers or a photo.
The rainy season brings out wild mushrooms, edible and poisonous alike, and some of them look almost identical. Folk tests such as boiling them with rice to see if it changes colour, dipping a silver spoon, or checking whether insects have nibbled them cannot confirm a mushroom is safe, and some toxins survive heat, so thorough cooking does not help. That is why the official rule is short: an unknown mushroom, an uncertain mushroom, do not pick it, do not eat it.
This article does not teach you to identify species, because judging by eye is exactly where people go wrong every year. It explains why the old tests fail, what this year’s numbers look like, and what to do if someone has already eaten a suspect mushroom.
The 2026 numbers
On 21 September 2026 the Office of Disease Prevention and Control Region 9 in Nakhon Ratchasima reported that from January to 21 September 2026, Health Region 9 recorded 335 cases of mushroom poisoning and 1 death.
| Province | Cases | Deaths |
|---|---|---|
| Chaiyaphum | 188 | 1 |
| Surin | 65 | 0 |
| Buriram | 58 | 0 |
| Nakhon Ratchasima | 24 | 0 |
| Total | 335 | 1 |
Work out the shares step by step:
- Chaiyaphum alone: 188 ÷ 335 ≈ 56%, more than half the region.
- The other three provinces together: 65 + 58 + 24 = 147 cases.
- 188 + 147 = 335, matching the total.
Most patients were women; people aged 65 and over were the largest group, followed by 55-64, and many were farm workers. In other words, people who have gathered mushrooms all their lives. Experience alone is not enough.
For the whole country, the Department of Disease Control’s weekly surveillance report in 2016 put hospital admissions from poisonous mushrooms at about 1,500 a year on average, with up to 24 deaths a year.
Why the folk tests fail
| Test people use | Why it cannot be trusted |
|---|---|
| Boil with rice, shallots or garlic and watch for a colour change | The Department of Disease Control says it does not work for the deadly Amanita group; a mushroom that leaves the rice white can still be poisonous |
| Dip a silver spoon and see if it blackens | Fails for the same reason |
| Insect or animal bite marks mean it is edible | Does not confirm safety |
| Picked from the same spot as last year’s safe ones | Does not confirm; in some fatal cases people picked from places they had eaten from before |
| Boil it long and hard | Some toxins are heat stable and are not destroyed |
If you need a test to feel sure, you do not really know the mushroom, and a mushroom you do not know should not be eaten.
The most dangerous group
The mushrooms behind most deaths in Thailand are toxic species of Amanita. Their local names vary by region: in the North, for example, het khai han and het mong kong; in Isan, het ra ngok hin, het ra ngak and het khai tai sak. They look very like the edible white Amanita (het ra ngok khao), especially when young, still a rounded egg shape, when they are almost impossible to tell apart by eye.
The main toxins, amatoxins and phallotoxins, are not destroyed by heat, and the Department of Disease Control warns that eating as little as half a cap can be fatal.
Symptoms, and the timeline that fools people
The Department of Disease Control’s documents give slightly different onset times. Its 2016 report says symptoms from the toxic Amanita group start at the earliest after 2-3 hours, usually after 6-12 hours. Its 2024 bulletin says first symptoms usually appear within 6-24 hours.
Worked example: a dinner at 6 pm
- 6 pm to about midnight: usually no symptoms yet. Everyone goes to bed as normal.
- About midnight to 6 am (6-12 hours after eating): nausea, vomiting, stomach pain, watery diarrhoea. By now most of the toxin has been absorbed, so stomach washing rarely helps. The gut symptoms last about 2-3 days.
- Around day 3-4: the stomach settles and many people think they have recovered. But liver values are rising, and the skin and eyes start to turn yellow.
- Day 4-16 after eating: in severe cases, death from liver or kidney failure.
The “getting better” phase in step 3 is the trap. Anyone with stomach symptoms after eating wild mushrooms needs a hospital, even if they feel better.
If someone has already eaten them
- Any symptoms, dizziness, nausea, vomiting, stomach pain or diarrhoea after eating mushrooms: call 1669 (Thailand’s emergency medical number) or go to hospital now. Do not wait and see.
- Bring the leftover mushrooms or photos, and tell the doctor what was eaten, how much and when.
- Tell everyone who ate from the same batch to watch for symptoms and go to hospital too.
- Do not make yourself vomit with fingers or raw egg white; it can cause choking and other complications.
- Do not self-medicate or go to a traditional healer instead; the Department of Disease Control warns against both.
- More advice: Department of Disease Control hotline 1422.
Unknown mushroom, uncertain mushroom: do not pick it, do not eat it.
Common mistakes
- Trusting the rice or silver spoon test. It does not work for the most dangerous group.
- Picking young caps because they taste better. Young is exactly when poisonous and edible look most alike.
- Eating wild mushrooms with alcohol. Officials warn some species react with alcohol and cause symptoms.
- Picking near sprayed fields or roadsides. Mushrooms can absorb toxins and heavy metals.
- Eating mushrooms raw or undercooked. Even edible ones should be cooked through.
- Older adults and people with liver or kidney disease eating wild mushrooms. The Department of Disease Control advises them to avoid wild mushrooms.
Summary
Rainy season is mushroom season, and mushroom poisoning season. In 2026, one health region alone recorded 335 cases. No folk test can confirm safety, the deadliest toxins survive cooking, and the early symptoms can ease while the liver fails. The safe choice is cultivated mushrooms from reliable sources, no unfamiliar wild ones, and a call to 1669 at the first symptoms after eating mushrooms. For choosing safe street food in general, see Thai street food safety: what to look at before you order.
Sources
- Eating young wild mushrooms is dangerous: half a cap of the khai han and ra ngok hin group can kill (Weekly Epidemiological Surveillance Report, 2016, Thai) — Department of Disease Control
- Mushrooms can be dangerous. If you don’t know, then don’t eat them (May 30 - June 5, 2024) — Department of Disease Control
- Officials warn of poisonous wild mushrooms during rainy season — Khaosod English
FAQ
Are wild mushrooms from a market safer than picking my own?
Not necessarily. Some poisonous mushrooms look very much like edible ones, especially when young, and a seller may not be able to tell. Officials advise buying cultivated mushrooms from reliable sources and skipping wild ones you do not know.
I vomited after eating mushrooms and now feel better. Do I still need a doctor?
Yes. The deadly Amanita group causes vomiting and diarrhoea for about 2-3 days, then patients feel better while the liver is being damaged. Death from liver or kidney failure can follow 4-16 days after eating.
Should I make myself vomit, with fingers or raw egg white?
No. Health officials warn this can cause choking and other complications. Go to hospital instead.
Ingredients and heat vary by kitchen and recipe. If you have a food allergy, ask before you order, every time.