No, but it will, if taken regularly or in large enough amounts, prevent your body from absorbing important nutrients. It could also induce dehydration, which could result in electrolyte imbalance, and, possibly, death.
exlax is a laxitive that helps soften poo * : )* and makes you have to go cleaning out intestines. if you take it after eating your body doesn't have enough time to get the nuitrients leading to malnutrition.
Yes, Exlax and other laxatives do help the poo move through you, but with all the dangers stated by the other answer when used too much or abused. To think otherwise is just ignorant.
Actually taking laxitives after eating only prevents about 10% of calories from being absorbed. It reduces bloating and for a day makes your stomach flatter but taking laxitives and doing nothing else is not going to make you lose any real weight. When your have Anorexia and Bulimia your stomach bloats quite a bit which is why feeling their stomachs flatten makes them feel like they're losing.