Somethings to try before you go onto medications (with a doctor's supervision) firstly is a change of diet. This is not as taxing as it may sound.
A really simple and easy thing to do is make the switch from white flour products and white rice to whole grain, whole wheat - any flour products, pasta or rice that hasn't been bleached and "enriched". These bleached foods have had all the nutrients stripped of them, and then synthetic ones that our bodies cannot process have been re-placed back into them. Whole wheat flour product and brown rice will have the opposite effect white flour/rice in that they contain a lot of fiber, and will help to break through and break away fecal matter stuck to the colon wall.
The next step simply is to cook at home. By cooking at home I mean to make things from scratch whenever possible, allowing for you to have complete control over your food. If it's a lasagna night, make the lasagna from scratch, allowing the noodles to be whole wheat, and the ground meat to be turkey instead of red meat.
Detoxifying the colon involves a good amount of fiber. The National Caner Institutes recommends 20-30 grams a day in the diet. Fiber helps your body through the process of elimination from the digestive system. It's easily obtained through whole grain foods, flax, dark, leafy greens, fruit, beans, and oats.
To fully detox, it is recommended to eliminate from the diet all processed foods, sugar, white flour products, most dairy, any produces that has been treated with pesticides, additives, preservatives, and of course, alcohol and caffeine. This may sound like I've just robbed you of food, but it is easy to replace these things with organic fruit and vegetables, home cooking, soy, rice, and almond milk products.
Drinking lots of water can help with detoxifying as well. When the colon "goes bad" it becomes toxic, and releases these toxins throughout the body, which is why there is such a variety of symptoms. Drinking plenty of filtered water can help eliminate the toxins from the rest of the body through other forms of elimination, such as through the urine and sweat glands.
Teas from dandelion root will help with this as well as support the liver and kidneys, which greatly suffer when there are toxins in the body. Garlic will cleans your entire system, though it is suggested that it is eaten raw or as close to raw as possible (a personal favorite of mine is brown rice, black beans, and finely chopped raw onion and garlic. It's cheap, healthy and tasty). Cayenne pepper added to your food will help the blood to circulate more efficiently, helping the elimination process.
When you can, make sure your vegetables are raw, and try and incorporate wheatgrass (that amazing super food) into your regular diet. You only need an ounce or two a day of wheatgrass juice to be set.
The liver is very important, as it's the organ that sorts through all that which your put in your body and gets rid of the toxins. A strong liver support is crucial to your over all well being and happiness. As mentioned before, dandelion is the liver and kidneys' ally, along with kelp, burdock root and a whole mess of vitamins: vitamin A, C, E, all the B's. Zinc and Selenium engaged with the mentioned vitamins act as antioxidants for the liver, protecting it from damage and will help to neutralize toxic substances.
Niacin is my personal best friend. It is actually simply B3 and acts as a powerful flush. I take two in one go for the intensity of the flush, which causes me to turn red all over and itch and itch and itch as the toxins rise to the surface of my skin and are released. THe itching is good as it helps to rid the toxins faster.