The popular fitness guru's manager Michael Catalano said he was battling "severe indigestion and discomfort while eating" for a few days.
Catalano said Simmons is already feeling better and is expected to make a full recovery. Catalano did not disclose where in California Simmons was hospitalized.
The 68-year-old fitness star has been out of the spotlight for more than three years, though he was thrust back in recently due to apopular podcast called, "Missing Richard Simmons."
The podcast, which was hosted by filmmaker Dan Taberski, delved into Simmons' whereabouts.
In March, ABC News confirmed that an LAPD detective conducted a welfare check on Simmons and said he's doing fine.
The detective described Simmons as a nice guy, funny, intelligent and articulate, saying Simmons "is just taking some time for himself."
The detective said Simmons is getting older, but he is still in pretty good shape.
ABC News contributed to this report.
Report a typo to the ABC13 staff