Dravida Munnetra Kazhagam (DMK) chief Karunanidhi was on Wednesday discharged from the Kauvery hospital.
He was admitted on December 1 for dehydration and allergy related issues.
The hospital in a statement said that Karunanidhi has improved substantially after medical treatment.
"All his vital signs and biochemical parameters have normalised now. He has been advised rest and Kauvery Hospital will continue to assess and provide the necessary medical and nursing care to facilitate his recuperation at home," it added.
he DMK chief was reportedly down with allergy-related ailment for over a month.