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Medium reported severity Media Coverage

Wakayama, Japan: city health officials say a man in his 70s was hospitalised after an AI photo check told him a poisonous wild mushroom was edible (MBS report)

According to Wakayama city’s public-health division, as reported by MBS (Mainichi Broadcasting) on 21 November 2025 and relayed by HuffPost Japan on 9 September 2026, a man in his 70s living in Wakayama city gathered wild mushrooms resembling hiratake (oyster mushroom) and shiitake in the mountains of Shimokitayama village, Nara prefecture, on 3 November 2025. The next day he photographed a mushroom with an electronic device and ran an AI identification, which answered to the effect that it was shiitake or hiratake and edible. The mushroom was in fact the poisonous tsukiyotake (moonlight mushroom); about 30 minutes after eating it he began vomiting and was briefly hospitalised. The city warned that judging wild mushrooms by AI or by picture books alone is dangerous. HuffPost Japan reports that Japan’s agriculture ministry issued a warning on 4 September 2026 against deciding edibility from search results or AI answers. The AI tool is not identified in the reports and the man’s exact exchange with it is not reproduced.

AI system
Unidentified mushroom-identification tool
Occurred
4 Nov 2025
Reported
21 November 2025
Event location
Japan
What the AI did
Communicated with the person
Reported harm
HospitalizationMedical Deterioration
Whose AI use
Their own AI use
Setting
Health · Everyday life
Evidence
AI involvement reported · Causal attribution supported · 2 sources, 1 underlying account
4 claims: 4 reported. 5 open questions
People reported harmed
1 person

AI system as recorded: AI image identification run on an electronic device, according to Wakayama city’s public-health division as reported by MBS, which answered that a photographed wild mushroom was shiitake or hiratake and edible (tool not identified)

What Happened

The gathering and the AI check. Wakayama city’s public-health division (生活保健課), as reported by MBS on 21 November 2025, says a man in his 70s living in the city gathered mushrooms in the mountains of Shimokitayama village, Nara prefecture, on 3 November 2025. HuffPost Japan, citing the MBS report, says the mushrooms resembled hiratake and shiitake, that on the following day he photographed a mushroom with an electronic device and ran an AI identification, and that the AI replied to the effect that it was shiitake or hiratake and could be eaten.

The poisoning. The mushroom was in fact tsukiyotake, a poisonous species. About 30 minutes after eating it the man began vomiting and was briefly hospitalised, according to the same account.

Official response. The MBS headline carries the city’s warning that judging mushrooms by AI or picture books on one’s own is dangerous. HuffPost Japan reports that on 4 September 2026 the Ministry of Agriculture, Forestry and Fisheries warned on social media that even experts can find mushrooms hard to tell apart and that deciding edibility from search results or AI answers is very dangerous, and that Gunma prefecture posted on 5 September that wild-mushroom AI identifications should not be believed as they stand.

Related case in the same report. HuffPost Japan also relays an Asahi Shimbun report of a nine-year-old in Wuhan, China, who became critically ill in June 2026 after an AI app judged a wild mushroom non-poisonous. That is a separate event and is not part of this case.

What is not established. The reports do not identify the AI tool or app, do not reproduce the exchange, and do not say how long the man was in hospital or whether he recovered fully. The MBS article body beyond its opening paragraph could not be read; the detail comes from HuffPost Japan’s summary of it.

Reported harm

According to Wakayama city’s public-health division as reported by MBS and relayed by HuffPost Japan, a man in his 70s ate a poisonous tsukiyotake mushroom after an AI identification of his photograph answered that it was edible shiitake or hiratake; he began vomiting about 30 minutes later and was briefly hospitalised.

Outcome

Resolved

The man was briefly hospitalised with vomiting, according to the city as reported by MBS. Wakayama city issued a public warning that self-judging mushrooms by AI or picture books is dangerous. HuffPost Japan reports that the agriculture ministry warned on 4 September 2026 that deciding edibility from search results or AI answers is very dangerous, and that Gunma prefecture posted a similar warning. No legal action is reported.

What remains unknown

  • Which AI tool or app produced the identification, and the exact wording of its answer.
  • How long the man was in hospital and whether he recovered fully.
  • Whether the AI identification was the only basis for his decision to eat the mushroom.
  • The content of the MBS article beyond its opening paragraph, which could not be read.
  • Whether he ate the mushroom on 4 November 2025, the day of the AI check: the 3 November gathering date is the city's account in the MBS opening paragraph (「同市在住の70代男性は11月3日」), the AI check 'the next day' is HuffPost Japan's summary (「この翌日」), and the eating date is not separately stated.

What the evidence supports

AI involvement: reported. HuffPost Japan, citing MBS’s report of Wakayama city’s public-health division, says the man photographed the gathered mushroom with an electronic device and ran an AI identification, and that the AI answered to the effect that it was shiitake or hiratake and edible; he ate it and was poisoned by tsukiyotake. The AI’s answer to the man is the described contribution (communicated_with), and the account connects that answer to his eating the mushroom. The tool is not identified and the exchange is not reproduced; the MBS body beyond its opening paragraph was not readable.

4 claims: 4 reported. What the statuses mean

Reported A man in his 70s living in Wakayama city gathered wild mushrooms resembling hiratake and shiitake in the mountains of Shimokitayama village, Nara prefecture, on 3 November 2025, according to the city’s public-health division.

Causal attribution. Wakayama city public-health division as reported by MBS and relayed by HuffPost Japan; one origin.

  • newsdig.tbs.co.jp(opens in new tab) supports · Japanese
    '和歌山市生活保健課によると、同市在住の70代男性は11月3日、奈良県下北山村の山中でヒラタケ'
  • huffingtonpost.jp(opens in new tab) supports · Japanese
    '2025年11月、70代男性が奈良県下北山村の山中で「ヒラタケ」や「シイタケ」に似たキノコを採取'
Reported The next day he photographed the mushroom with an electronic device and ran an AI identification, which answered to the effect that it was shiitake or hiratake and edible.

Causal attribution. MBS report of the city’s account as summarised by HuffPost Japan; the tool is not identified and the exchange is not reproduced.

  • huffingtonpost.jp(opens in new tab) supports · Japanese
    'この翌日、そのキノコを電子端末で撮影してAI判定を行ったところ、AIが「シイタケかヒラタケで食べられる」という旨の回答をしました'
  • newsdig.tbs.co.jp(opens in new tab) supports · Japanese
    '被害男性が毒キノコを食べてしまった背景には、AI判定がありました'
Reported The mushroom was the poisonous tsukiyotake; about 30 minutes after eating it the man began vomiting and was briefly hospitalised.

Causal attribution. City account as reported by MBS and relayed by HuffPost Japan; the link between the AI answer and the eating is the city’s account as reported.

Reported Japan’s agriculture ministry warned on 4 September 2026 that deciding whether a mushroom is edible from search results or AI answers is very dangerous.

Causal attribution. HuffPost Japan’s report of the ministry’s social-media warning; the ministry post itself was not inspected.

  • huffingtonpost.jp(opens in new tab) supports · Japanese
    '農林水産省は9月4日、SNSを通じて注意を呼びかけました。キノコは「専門家でも見分けが難しい場合がある」として、「検索結果やAIの回答で食用かどうかを判断するのは大変危険です」と警鐘を鳴らしています'

Sources

2 sources inspected, from 1 underlying account. Sources that repeat one account do not corroborate each other.

How the sources were read, and where the events happened

Read in Japanese and translated into English by the research agent (an AI) on 2026-10-08 (HTTP 200); no human translator or reviewer. HuffPost Japan editorial piece of 9 September 2026 that summarises the MBS report of the Wakayama case and the agriculture ministry’s warning. Applies to s1.

Read in Japanese and translated into English by the research agent (an AI) on 2026-10-08 (HTTP 200). Only the headline and the opening paragraph were readable; the rest of the article sits behind a read-more control that the fetch did not expand. MBS report attributed to Wakayama city’s public-health division; same origin as s1. Applies to s2.

Event countries: Japan. Affected-person countries: Japan. Court countries: Unknown.

The mushrooms were gathered in Shimokitayama village, Nara prefecture, and the case was handled and announced by Wakayama city, where the man lives; both are in Japan. No court is involved.

Reviewed for publication 2026-10-08: Published as a core case on one official origin carried by two outlets: Wakayama city’s public-health division, through an MBS report summarised by HuffPost Japan, says a man in his 70s ran an AI identification of a photographed wild mushroom, was told it was edible, ate the poisonous tsukiyotake and was briefly hospitalised with vomiting. The AI’s answer to the man is described and connected to the harm. Every claim is attributed to the city’s account; the tool and the exchange are recorded as unknown.

People described

A man in his 70s living in Wakayama city, Japan, who gathered wild mushrooms in Nara prefecture and ate one after an AI identification called it edible (not named)

People reported harmed in this case

1 person

1 AI participant · 0 other people harmed

One person: the man in his 70s who ran the AI check and ate the mushroom (own use). No other person is reported poisoned.

Counted once within this case. The same person may appear in other cases. This count does not establish AI causation.

Tags

#mushroom-identification#image-recognition#poisoning#hospitalisation#foraging#japan#wakayama

Cite this case

Compiled per our published methodology: verification statuses, sourcing standards, and corrections process.

APA

NOPE. (2026). Wakayama, Japan: city health officials say a man in his 70s was hospitalised after an AI photo check told him a poisonous wild mushroom was edible (MBS report). AI incidents. https://nope.net/incidents/2025-wakayama-japan-ai-photo-check-called-poisonous-mushroom-edible-man-hospitalised

BibTeX

@misc{2025_wakayama_japan_ai_photo_check_called_poisonous_mushroom_edible_man_hospitalised,
  title = {Wakayama, Japan: city health officials say a man in his 70s was hospitalised after an AI photo check told him a poisonous wild mushroom was edible (MBS report)},
  author = {NOPE},
  year = {2026},
  howpublished = {AI incidents},
  url = {https://nope.net/incidents/2025-wakayama-japan-ai-photo-check-called-poisonous-mushroom-edible-man-hospitalised}
}

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