Yellen also said that she and the other guests did not feel ill or awkward after consuming the meal.
"So, I went with this large group of people and the person who had arranged our dinner and the order [said] there was a delicious mushroom dish. I was not aware that these mushrooms had hallucinogenic properties. I learned that later," Yellen told a American broadcaster.
In addition, the Treasury Secretary said she had read that mushrooms would not cause any adverse effects if cooked properly.
"I'm sure they were [cooker properly] at this very good restaurant," Yellen said, "All of us enjoyed the mushrooms [at] the restaurant and none of us felt any ill effects from haven eating them."
During her visit to Beijing from July 6-9, Yellen held talks with top Chinese economic policymakers in an attempt to improve strained diplomatic and trade relations between the United States and China.