Police say they found Sheen, 45, drunk and naked in a trashed suite at New York's Plaza Hotel this morning. Sheen's representative said the actor was not drunk, but suffering from a severe allergic reaction.
Sheen was not arrested because nobody made a formal complaint against him, New York Police Commissioner Ray Kelly said.
Watch the full interview tonight on "Nightline" at 11:35 p.m. PT for exclusive TMZ video.
In an interview excerpt released by "The Joy Behar Show," Richards said she "did help him [Sheen] at the hospital" after the incident, but did not want to disclose what she knew out of concern for her relationship with Sheen and the welfare of their daughters Sam, 6, and Lola, 5.
"They're at an age when they can start to understand," Richards said in an excerpt of an interview on the HLN show this evening. "They have no idea what went on and ... our stuff happened when they were much younger, which I'm so grateful for. We're in an amazing place. We've been getting along great for the last year, year and a half.
"As far as that situation, I'm trying to protect the girls from it as much as possible," Richards said.
"I'd rather leave that for Charlie to discuss," she said. "I do know what happened."
Sheen was found in the suite after hotel security called 911 at 2:07 a.m. today, according to ABC New York station WABC-TV. He was taken to New York Presbyterian Hospital for treatment for alcohol abuse and psychological evaluation.
Police sources told WABC-TV that Sheen appeared to be highly intoxicated and was unable to communicate in a rational manner. He was believed to have been drinking since 8 p.m., police said.
The room -- including tables, chairs and a chandelier -- was in disarray. When police arrived, Sheen was in a rage, saying someone had stolen his wallet.
According to the New York Post, Sheen returned to his room with an unidentified woman after a night out and blew up when he discovered his wallet was missing.
Richards told Behar she was on a family vacation to New York with Sheen and their daughters.
Despite what police have said, a representative for Sheen denied that the actor was hospitalized because he was drunk.
"What we are able to determine is that Charlie had an adverse allergic reaction to some medication and was taken to the hospital," Sheen's publicist said in statement to ABCNews.com.
Later, publicist Stan Rosenfield e-mailed an update: "Charlie Sheen has been discharged from a hospital in N.Y. and is returning to L.A. today. Everything else is speculation."
Sheen, the star of CBS' "Two and a Half Men," has had a heap of problems of late.
In August, Sheen pleaded guilty to misdemeanor assault in a domestic abuse case involving his wife, Brooke Mueller, in exchange for the withdrawal of two other charges, including a felony. He was sentenced to 30 days in a California rehabilitation center, 30 days of probation and 36 hours of anger management counseling.
Sheen had been charged with second-degree assault, menacing and criminal mischief after allegedly brandishing a knife at Mueller Dec. 25, 2009, in Aspen, Colo.