Sheen, the star of Platoon, Wall Street and the son of Hollywood veteran Martin Sheen, was admitted to the Los Robles Medical Center in the early hours of Wednesday, complaining he had difficulty walking and was experiencing tingling in his hands. Some reports suggested he arrived at Emergency in a state of hysteria and had to be tied down.
A visibly distraught elder Sheen arrived at the hospital late Thursday to quash reports being broadcast in Los Angeles that his son had suffered a stroke or had died.
"The first thing I want to assure you is that my son, Charlie Sheen, is very much alive," Mr Sheen said. "He eating, he's talking, he's aware".
No details were available on what kind of drug Sheen had taken. Three years ago, he told the New York Post of his battle with ecstasy. He said: "Ecstasy should be called the drug from Hell - because that's where it leaves you."
Mr Sheen has suffered repeated bouts of bad publicity, dating back to 1990 when he checked himself into a drug and alcohol rehabilitation clinic. In 1995 he was sued by a woman who claimed he struck her around the head after she refused to have sex with him.
Most humiliating, perhaps, was his leading role in the 1995 federal trial of Hollywood madam Heidi Fleiss, purveyor of prostitutes to the stars. He admitted he had ordered at least 27 call girls from Fleiss and had run up bills with her totalling $50,000.
At the end of 1996, after ending a six-month marriage to model Donna Peel, Sheen announced he was becoming a born-again Christian. Fast living, he said then, "was a lot of fun, but there is such a thing as too much fun".
Martin Sheen said he was hopeful he would be able to persuade his son to re-enter a rehabilitation programme after his recovery from the latest scare.
He recalled how his actor friend Carroll O'Connor had been devastated when his son killed himself in March 1995 after struggling for years to defeat a cocaine addiction. "I'm sorry Carroll didn't get the chance that we have. This is not an easy moment in our lives, but it's a necessary one. Our hope is that he will accept recovery and be fine."