Like everyone has already said, diet pills are bad news. Stick to working out, and try to eat healthier. And drink lots of water!!
Honestly, I've used diet pills before and I've only had one that I liked. I wish I could remember the brand, but Walmart had actually stopped selling them.
All the pill did was make me feel fuller all of the time, gave me energy for the day and made me extremely thirsty.
I wouldn't suggest pills though. Ever since I've started working out, I get the same results AND have a huge sense of accomplishment.