The 69-year-old star's wife Dimple, from whom he is separated, is remaining by his side, his manager told NDTV Movies.
"He is unwell, and at home. He has stopped food-intake for three to four days. Dimpleji is continuously by his side and his daughter Rinke also visited today," the manager said.
Earlier in April, Khanna had been admitted to hospital following complaints of "uneasiness and weakness".
The veteran actor, considered Bollywood's first superstar, has acted in over 150 films.
Khanna dominated the film industry in the 1960s and 1970s with films like Aradhana, Anand and Bawarchi.
His eldest daughter Twinkle is married to actor Akshay Kumar.