Fragment taken from www.wholehealthmd.com
Blackberries are considered to be an astringent because of their high tannin content. Studies show that tannins tighten tissue, lesson minor bleeding, and may help to alleviate diarrhea and intestinal inflammation. German health authorities recommend blackberries for mild infections including sore throats and mouth irritations. Traditionally, blackberries have been used to alleviate hemorrhoids because of their rich tannin content. Scientists have also reported anti-tumor properties associated with tannins found in some varieties of blackberries. Future research will explore the implications for treating human cancer. Overindulgence of tannin-rich blackberries may lead to constipation.
Blackberries abound in antioxidants, such as anthocyanin pigments, responsible for the purplish-black color of blackberries and may impart health benefits because of their antioxidant properties. Additional antioxidants in blackberries are vitamins C and E, and ellagic acid; all may provide protection against cancer and chronic disease. Cooking does not seem to destroy ellagic acid, so even blackberry jams and desserts retain ellagic acid health benefits. Interestingly, blackberries are a natural source of salicylate, an active substance found in aspirin. Potential benefits have yet to be explored and some experts advise caution to particularly aspirin-sensitive individuals. Because of their many tiny seeds, blackberries are a source of soluble fiber, such as pectin.