Depends on what's causing the constipation. Is it chronic? Have you had it for a long time? If so, then you may have slow peristalsis, or a "lazy gut". If that is the case, you need to take a product which contains magnesium oxide. This provides oxygen to the bowel and will speed up peristalsis. Usually, peristalsis can be improved by using this product for a time and then you will no longer need it. If it is just occasional constipation, then getting exercise, drinking enough water (half your weight in water; ex. 150 # = 75 oz water) every day, getting enough fiber in the diet, and taking probiotics can help. Digestive enzymes help the stomach digest food so these can be an aid as well.
Probiotics do help with constipation and are found in yogurt. Also, make sure you are getting plenty of water and fiber in your diet.