Prunes as a laxative are considered highly effective. The laxative effect comes from the prunes' ability to draw water into the intestines, the fruit's high concentration of insoluble fiber and a compound they contain called dihydrophenylisatin. When consumed in a reasonable serving size, prunes as a laxative are typically safe and have minimal side effects.
There are three reasons for the efficacy of prunes as a laxative. First, these dried plums are concentrated with the simple sugars fructose and sucrose. These sugars are not easily broken down in the digestive tract and, as a result, the undigested sugars pull water from the body and concentrate it in the stool. The extra water softens the bowel movements and eases the passage of fecal matter.
The insoluble fiber prunes contain increases the bulk of a bowel movement, which helps to move the fecal matter more quickly through the body. The high fiber content also helps to improve the regularity of bowel movements. The dihydrophenylisatin contained in prunes serves as a compound that promotes the contractions in the intestine needed to pass fecal matter.
There are a variety of ways to increase the amount of prunes in the diet. Prunes can be eaten whole, added to salads or meat-containing dishes and eaten with cheese. If the taste of whole prunes is not tolerable, prune juice can be ingested or mixed with apple juice once or twice a day.
The recommended daily amount of prunes is four to five whole prunes per day or about 1 cup (237 ml) of prune juice for an adult. When someone suffering from constipation starts to use prunes as a laxative, he should start with a small quantity. This quantity would be one to two prunes or about one quarter cup (59 ml) of prune juice. Once the body has become used to the effects of the prunes as a laxative, the amount taken per day can be raised or held as it is if the lower dose is effective. If the recommended daily dose is used right from the start, the constipated person may experience cramping and diarrhea.
Besides prunes, there are many other foods that can be used as natural laxatives to relieve constipation. Fruits, such as apples, melons and oranges, with their high water content, can help constipation. Vegetables, such as carrots, broccoli and cauliflower, are high in fiber, helping fecal matter to move though the intestines. Raw apple cider vinegar is also touted as a good natural laxative, promoting the growth of the natural flora in the gut and easing constipation.