This is the second time in the past five days that Mulayam had to be hospitalized. Earlier, he was admitted to the hospital on Wednesday and discharged on Saturday.
He was said to be suffering from chronic constipation and had undergone colonoscopy.
"There is swelling in his intestines but he is stable and should recover soon. Gastro-surgeon are monitoring his health," said Dr Rakesh Kapoor, director of the Medanta hospital.
Pragatisheel Samajwadi Party Lohia chief Shivpal Singh Yadav said Mulayam Singh Yadav's health was fine and urged the people to pray for his long life.
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