Chongqing hot pot restaurant investigates black tongue coating in four diners

Four diners in Chongqing experienced abnormal black tongue coating after eating at the Jingxuan Yanqing Hot Pot (Renhe Store) on October 16. One individual reported that the discoloration had not fully subsided several days after the meal.

The restaurant staff suggested the phenomenon might be a chemical reaction between the customers' self-brought lemon water, the iron pots used in the restaurant, and lotus root. Local market supervision authorities have collected food samples for laboratory testing to determine the cause.

The customers, led by a man surnamed Yang, initially suspected nitrite poisoning. While hospital examinations did not identify a specific cause and doctors recommended cleaning the tongue, the diners withheld payment for the meal, which exceeded 2,000 yuan, due to health concerns.

Food safety experts noted that a “pseudo-black tongue” phenomenon exists, often caused by food, pigmented drinks, or certain medications, which typically fades after cleaning. A similar incident occurred earlier in 2024 at another Chongqing hot pot establishment, which was attributed to improper iron pot maintenance.