Senna will clear you out.

Fibre will make you regular. My favorite form of fibre is psyllium husk tablets with a huge glass of water.

With the addition of a fiber supplement, eating more fruits and veggies might help too. And staying hydrated.

You might also want to take a look at your diet for possible food intolerances. I discovered that eliminating both dairy and gluten from my diet got rid of the very same problems.

Keeping a food diary is good way to track this and also gives your dr a valuable tool for diagnosis. Write down everything, including even a glass of water or stick of gum. Be honest. Also keep track your symptoms every day, including emotional ones (yes, food can affect your mood). Food intolerances often have a way of sneaking up a few days after the offending food is consumed.

Probably more info than you were looking for.