The 22-year-old forward, who joined Liverpool during the January transfer window for £35m, will win his second England cap against Ghana on Tuesday.
"Not only Andy likes to drink beer," said Capello, ahead of the Wembley friendly against the Black Stars. "He needs to improve, to drink less.
"I spoke with him, in private. He's young - his behaviour is important."
Capello's warning is reminiscent of former England manager Graham Taylor speaking about Paul Gascoigne's "refuelling" in 1993.
Before joining Liverpool, Carroll experienced a number of off-field problems at Newcastle United.
"He needs to be careful at every moment because when you play with the England national team you are the focus of the fans, the newspapers, the photographers, the people that live around him," added Capello.
Carroll, who made his debut for England in November, has only just started playing for Liverpool following a lengthy absence due to a thigh injury, but Capello maintained no deal had been struck with the Anfield club over how long the striker should be involved for.
"Absolutely no-one has rung me and we have not spoken with Liverpool," said Capello.
"He needs to play. Liverpool will be happy for him to play. It is a friendly and he can play up to half-time, or more. For this reason, the game is important for him and for me."
Meanwhile, despite struggling with some of the finer points of questions put to him at media conferences, Capello - who has been in the job for three-and-a-half years - says his English is good enough to get his messages over to the players.
"How many languages do you speak?" he challenged. "When I speak with the players they understand everything and that is what is important in this job.
"If I need to speak about the economy or other things, I can't, but when you speak about tactics, you don't use a lot of words.
"I don't have to speak about a lot of different things. Maximum 100 words."
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We all know Carroll is a fairly unpleasant, unprofessional character, I don't think Capello should be coming out criticising him publicly like this though. He might go out and get pissed, or hit Capello's wife. Capello's PR skills really are severely lacking.