Meg Ryan's luminous central performance as an alcoholic is the driving force behind "When a Man Loves a Woman," which distinguishes itself in some ways, yet never completely pulls itself out of the inevitable cliches that come with this territory. Still, Ryan is so compelling and the message here so hopeful, it's hard not to find the film compelling.

Ryan plays a San Francisco schoolteacher, with a loving husband — airline pilot Andy Garcia — and two young daughters. But she is becoming more and more dependent on a drink, or two or three, to get her through the night — and, ultimately, through the day.

When the film begins, her drinking is already a problem and she recognizes it but can't quite make herself do anything about it — until one boozy afternoon results in a near-tragedy.

So, she goes into detox, while Garcia tries to take care of the kids, with help from their overworked, put-upon babysitter (feisty Lauren Tom, of "The Joy Luck Club").

At this point, there is a shift in emphasis from Ryan to Garcia, which essentially sends the film reeling in an unexpected, and not entirely satisfactory, direction.

When Ryan returns to the family and strives to stay sober, it becomes apparent that Garcia may have preferred Ryan being more dependent on him, and her newfound independence is distressing and puts severe strain on the marriage.

There is no explanation of Ryan's condition. This movie is clearly about what to do about the problem — not how to avoid or recognize the problem early on.

The story element that is unique here, and which gives the film more power, is the way it demonstrates how alcoholism affects an entire family, as opposed to one person. The kids (Tina Majorino and Mae Whitman) are not mannered Hollywood types and Ryan and Garcia are utterly convincing in their roles.

But the movie is only fulfilling in fits and starts. There is great potential that is alternately tapped and untapped, some sequences that are affecting and genuine, while others seem artificial and emotionless. (And the one scene that Ellen Burstyn has, as Ryan's obnoxious, domineering mother, is so fleeting that she might as well have been completely cut from the film.)

Director Luis Mandoki ("Born Yesterday") goes for a slick Hollywood sheen and has no problem with broad strokes to quickly gloss over details. He also relies too heavily on music videos as segue devices, a convention that has all but worn out its welcome.

Still, the story does come together nicely in the end, with a touching and hopeful conclusion. But wouldn't it be nice if the journey were more satisfying?

"When a Man Loves a Woman" is rated R for considerable (and gratuitous) profanity, with some vulgarity, sex, brief nudity and violence.