I'm not going to preach about the dangers of diet pills,cause I've taken them myself(recovered anorexic-four years) and some of them made me feel like crap or even crazy and sometimes I felt like my heart would just beat out of my chest.
There is one pill that even doctors say is ok because it used to be available only with a prescription and under a different name.It's called Alli and,when taken with a healthy diet,can aid weight loss by 50%.So if you lose 20 pounds with regular diet and exercise,you can lose 30 with Alli.You can have up to 15 grams of fat at a time(take one pill per meal)or you get explosive diarrhea which nobody likes.
Good luck!