The Health, Labor and Welfare Ministry decided Friday to ban the sale of foods containing processed "katuk," a leafy green vegetable, by the end of next week.
The ministry fears that the vegetable, known scientifically as sauropus androgynus, may have detrimental health effects, officials said.
Although the vegetable originated in South Asia, it is mainly grown in Okinawa Prefecture.
It is touted as nutritious and good for slimming diets, and is often consumed in powdered or tablet form.
The ban will not apply to fresh katuk.
A sub-panel of the ministry's Pharmaceutical Affairs and Food Sanitation Council recommended a ban on sales in light of a recent series of cases in which people who have consumed health foods containing katuk in powdered form have caught bronchitis.
The Cabinet Office's Food Safety Commission has already concluded that katuk is suspected of causing the bronchitis cases.
This constitutes the first ban on a food product whose negative health effects have not been confirmed.
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