Sheen's condition at Cedars-Sinai Medical Center in Beverly Hills wasn't immediately known. His rep, Stan Rosenfield, tells PEOPLE, "All I know is what I was told – that he was having severe abdominal pains."
Sheen's parents, actor Martin Sheen and wife Janet, went to the hospital and "are very concerned," a source says.
Fire department officials confirm they responded to an address that matches Sheen's in a posh gated community in Beverly Hills after receiving a 911 call at 6:35 a.m.
"The call was medical in nature," LA City Fire Dept. spokesman Devin Gales tells PEOPLE. "We transported at least one individual from that location to a local hospital."
Sheen, 45, has been in the headlines frequently over the past year due to a messy split from his wife Brooke Mueller and after allegedly trashing a hotel suite while in the company of an adult film star in New York.
CBS entertainment chief Nina Tassler told reporters earlier this month she had a "high level of concern" about his personal life but was so far happy with his professional conduct.
The show is on hiatus this week and resumes production on Monday.
Additional reporting by KEN LEE