It was her fitness instructor Mari Winsor who understood how bad Melanie Griffith's chronic neck pain had become. Winsor has been teaching Pilates, the muscle-stretching exercise regimen, to Griffith for two years and had witnessed her occasional agony. "The neck has been an issue ever since I've known her," says Winsor, 50. "She had to be careful."

Griffith, 43, was careful, but her reliance on prescription medication apparently was heading out of control. So, on Nov. 9, on the advice of her doctor, the self-described "addictive personality" checked herself into the Daniel Freeman Hospital in Marina Del Rey, Calif., in order to "step down"—as she called it—from her growing dependence on prescription drugs. It's the third time Griffith has faced substance problems. Her previous struggles, though—the most recent in the early '90s—were alcohol and cocaine related.

Griffith, a mother of three (Alexander, 15, with ex-husband Steven Bauer; Dakota, 11, with ex Don Johnson; and Stella, 4, with husband Antonio Banderas, 40), "nipped this in the bud immediately," says Winsor. And the actress—who this spring revealed her thus-far-unsuccessful fertility treatments—now plans to share her recovery effort online. "We're going to make sure we educate people," says Liz Edlic, Griffith's partner at OneWorldLive.com, a Web site where Griffith hopes to chronicle her recovery. As for any echoes of Griffith's fast-living youth, Edlic says, "That's her past. She has an abundant and wonderful life."