The "Two and a Half Men" actor, 45, was taken out of his L.A.-area home via stretcher and loaded onto an ambulance around 7 a.m., according to TMZ.
Explains the rep to Us: "He was having severe abdominal pains and went to the hospital." Sheen remains at the hospital, the rep added.
Earlier this month, the notoriously hard-partying actor -- who has spent numerous stints in rehab for his addictions -- was spotted downing vodka shots at the Palms Hotel in Las Vegas. That followed Sheen's Oct. 25 drunken, nude bender at NYC's Plaza Hotel. On Christmas Day 2009, Sheen got into a violent altercation with wife Brooke Mueller.
An insider recently told Us that Sheen ditched the sober coach hired following his Plaza Hotel incident. "He has not heard from Charlie since he told him not to start [drinking] New Year's day."