The most common uses were for treating diarrhea, sore throats, and wounds. These same constituents are also helpful for soothing sore throats . In general, the roots are stronger but less available than the leaves. The German Commission E monograph recommends 4.5 grams of blackberry leaf per day. Three or more cups per day should be drunk.
Tannins can cause nausea and even vomiting in people with sensitive stomachs.
Individuals with chronic gastrointestinal problems might be particularly at risk for such reactions. Taking blackberry with food may reduce risk of gastrointestinal problems in some people. At the time of writing, there were no well-known drug interactions with blackberry. For the convenience of the reader, the information in the table listing the supplements for particular conditions is also categorized. Castleman M. The Healing Herbs.