I do Colon Cleanse once every month. Usually I take Magnesium Oxide for three successive days that does a good job of cleaning my intestines.
Further the capsules Triphala is by it self, mildly laxative and contains anti parasitical constitution.
The Botanical Ingredients are (Latin names)
Chebulic myrobalan (Laxative and works well for Tapeworms)
You can find this online or most herbal and nutritional food stores do carry. Do a search on "Triphala OR Threepala OR Trifala" on a major search site and read all related info before doing a purchase. Also note down the brand names and prices and see if you can find an East Indian grocery store in your neighborhood and inquire from them if they carry it. Compare the prices and usually they are cheaper since they import it directly from India. But do look for expiration date and how fresh and presentable the packing looks. Because some Indian stores may have very old stocks, I know large metropolis do have street full of Indian shops. E.g.: Chicago Devon St.
Cost: Mostly comes in small bottles with 60 to 90 capsules, costs about $15 to $20