There are different types of diet pills on the market. We will list some according to their characteristics. There is a group who are, in fact, diuretics and / or laxatives. They are usually made based on natural products such as plum and green tea. In the balance may notice that lowered weight. But that is because fluids are lost (and some solids) so do not bring any long-term benefit.
Another group is anti-fat pills. They must have seen some commercial in which the pads shown as "encapsulated" by preventing fat from being absorbed by the body. There are actually tested a single drug (Xenical) is sold only by prescription to people with serious obesity problems. Although not many doctors recommend as it has many side effects.
Another group is supposedly quenching pills these pills are composed of fibers that swell in the stomach and give us away hunger. Assuming you pass this seriously if we are not used to consuming fiber may be harmful to health, especially if we have intestinal problems. Fat burning pills. These latter are well known but not at all effective. Advertising on the TV says that thanks to these pills making our metabolism speeds up to spend more calories without doing anything. Something completely false.
The only way to lose weight is to expend more calories than you eat. This is accomplished by exercising more and eating less (or just eating in a more healthy). My recommendation is do not be tempted too much with this weight loss pills because only lose your time and jeopardize your health. There is no magic drug for weight loss.