First of all, for the purposes of full disclosure, I wanted to let people know that I was on this medication, which is also known as Orlistat. The prescription drug was much stronger and so were the side effects.
              Here's the bottom line on this medication:
You can lose weight without it, if you commit to a sensible eating plan and exercise. I personally prefer one that limits carbs or has a balanced approach to carbs, something like the South Beach Diet South Beach Diet.  But if you feel you need to see some quicker results, then here are the pros and cons about Alli :
   
     Will it help you lose weight? Yes, it can but don't expect miracles. This is a much lower dosage than the prescription form and it won't let you drop 20 pounds immediately.

      But it CAN help. For example, the brochure states that if you would normally lose 5 pounds with diet and exercise, Alli could cause you to lose 2-3 more pounds, bringing the total to as much as 8 pounds WHILE EATING THE SAME FOODS and exercising the SAME amount. Why? Because it does reduce the amount of fat you absorb.
 
        Even so, you can STILL gain weight if you don't follow a sensible eating plan and get some exercise. This isn't a magic potion but an AID. If you are one of those people who would get excited by seeing an extra few pounds come off and if it would MOTIVATE you to stick to your diet, then I could see how Alli would be of benefit to you.
  
       On the other hand, you can also expect to have some discomfort if you cheat and eat high fat foods, including gas, looe stools, etc. I would think that could be enough to deter people from eating THOSE foods but apparently some people do cheat, anyway.
The bottom line? If you are motivated, willing to make changes, get some exercise and committed to this plan, you will lose more weight than without taking the pill. Just don't expect miracles, but a nice, slow but steady loss.
A nice side effect? The possible lowering of cholesterol, another reason to try this.