Not really for the ab area -- like HH said- you can't spot reduce. Its all about diet there. Women tend to hold their bodyfat in the stomach / waist / hips. If you start doing crazy amounts of sit-ups & ab work, all it really does is make you thicker in the waist. The goal is decrease the bodyfat in that area, but it generally takes longer -- when you diet, train & do cardio -you decrease bodyfat at the same rate across your whole body. But if you happened to hold more fat cells in certain areas, like stomach / waist / hips, then losing , say 5% bodyfat will be less noticeable where there is more fat cells than where there is less. -- i.e. the waist/ stomach / hips. So you just get a good diet & training in place & keep plugging away.
She can also add in Yohimburn as a topical fat burner that will help -- but again its not a magical potion . Still takes diet. And by "diet", I mean a consistent diet w/o random cheats & binges, along w/ consistent training & some cardio.
For a good example of this -- take a look at the stickies at the top or print them out for your wife - Shadow's Project & Project Summary.