The 67-year-old actor was taken to H N Reliance hospital by his family on Wednesday morning.
The Bollywood actor returned to India last September after undergoing treatment for cancer in the US for almost a year.
In February, Kapoor was hospitalised twice due to his health issues.
After his return to Mumbai, he was again admitted to a hospital with viral fever. He was discharged soon afterwards.
Kapoor, who has been quite active on social media, hasn’t posted anything on his Twitter account since April 2.
The actor recently announced his next project, a remake of Hollywood film “The Intern”, also featuring Deepika Padukone.