Ford also said he would take a leave from his campaign for re-election. One of his rivals in the Oct. 27 election called on the mayor to resign.
"I have a problem with alcohol, and the choices I have made while under the influence. I have struggled with this for some time," Ford said in statement late Wednesday.
"I have tried to deal with these issues by myself over the past year. I know that I need professional help and I am now 100% committed to getting myself right," he said.
The Globe and Mail newspaper said it has viewed a second video of Ford smoking what appears to be crack cocaine in his sister's basement. The national newspaper said two Globe reporters viewed the video from a self-professed drug dealer showing Ford taking a drag from a pipe early Saturday morning.
The video is part "of a package of three videos the dealer said was surreptitiously filmed around 1:15 a.m., and which he says he is now selling for 'at least six figures,'" the paper reported.
Ford did not address the reported video or make any reference to crack cocaine in his statement.
News reports of an earlier video of Ford apparently smoking crack first surfaced last May, igniting a media firestorm. The mayor denied the existence of that video for months but after police said they had obtained it, Ford acknowledged that he smoked crack in a "drunken stupor." He rebuffed intense pressure to resign and launched his re-election bid earlier this year. The first video has never been released to the public.
Ford's lawyer, Dennis Morris, said he spoke to Ford Wednesday and said the mayor has accepted that he has a problem.
"He acknowledges he has a substance abuse problem and he wants to do something about it," Morris told The Associated Press.
Ford did not specify how long his absence would be or what type of treatment will seek. Morris said Ford told him it was his intention to enter rehab but could not offer more details.
"Today a person could say they are going to do this. And tomorrow they could change their mind. Let's hope that's not the case," Morris said.
The mayor was seen leaving his west-end Toronto home Thursday morning in a two-vehicle convoy but did not respond to reporters' questions or say where he was going. In a letter to the city clerk, Ford said simply indicated that he is taking a leave of absence and will provide updates on his status, according to Jackie DeSouza, a spokeswoman for the City of Toronto.
Toronto police spokesman Mark Pugash will they will investigate the new video. "Investigators would like to see the latest information," he said.
Ford is the target of an ongoing drug-related investigation but has not been charged. His friend and former driver Alexander Lisi is facing extortion charges over alleged attempts to retrieve the first crack video from an alleged gang member. Recently released police documents note that meetings between Ford and Lisi are "indicative to that of drug trafficking" and that the two have been in constant contact during the investigation.
Ford has careened from one scandal to another, including public drunkenness and an appearance in another video that showed him threatening "murder" in an incoherent rant. Toronto's city council has stripped him of most of his powers.
Also on Wednesday, The Toronto Sun said that it had obtained an audio recording of Ford making offensive remarks about other politicians at a bar on Monday night.
Ford said last year that he quit drinking alcohol after having a "come to Jesus moment" but later acknowledged that he drank again. A number of recordings of the mayor intoxicated have surfaced since.
Ford acknowledged "rocky moments over the past year" during his official campaign launch earlier this month but vowed to fight harder than ever to win re-election.
In in his statement Wednesday, he asked for continued support. "I love the people of Toronto, I love being your mayor and I hope you will continue to stand by me," he said.
A message left with Ford's chief of staff was not returned.
John Tory, who is running against Ford in the election, said he is relieved that Ford is seeking help but that the mayor should resign.
"Like Torontonians across the city, I am deeply disappointed by these revelations of Mayor Ford's behavior," Tory said. "For the good of the city, I call on Mayor Ford to resign."
The premier of Ontario province, Kathleen Wynne, who was out for a Thursday morning jog, said the situation with Ford has been a distraction for a long time. She said she has long worked directly with Toronto Deputy Mayor Norm Kelly.
"Rob Ford needs to deal with his personal issues," she said. "I have been and will continue to deal with deputy mayor Kelly."