Beijing: The number 420 has a different connotation in China from now onwards.

That is the number of stones doctors there removed from a 55-year-old gypsum tofu lover’s kidney.

They conducted a two-hour emergency surgery on the left kidney of He Dong at Dongyang People’s Hospital in Jinhua city of East China’s Zhejiang province. A CT scan for abdominal pain showed his kidney were filled with stones, the statesman.com reported.

Dong told doctors that he ate a large daily diet of gypsum tofu, a local food with a high concentration of calcium sulphate.

“Soy products, especially gypsum tofu, are very high in calcium, the excess of which cannot be excreted from body without a sufficient intake of water,” said the doctor Wei Yubin.

“The operation almost took two hours. We spent 45 minutes just taking out the tiny stones. After the operation, my hands and legs were both numb,” Yubin said.

The doctors removed the 420 stones one at a time with forceps, the Mirror reported.

Dang said he didn’t like drinking water but has been ordered to change his eating habits.

The doctors have advised Dang to cut down on the daily consumption of tofu as he kept the stones as a souvenir.