allergic reaction<\/a>. While this rarely occurs with eating fresh berries, patients using bilberry extract may find that they develop skin sensitivity issues to the oil, mainly if they apply it directly to their skin. <\/span><\/p>\n\n\n\nThe tannins found in bilberries are responsible for creating allergic reactions, and if you have allergies to other foods like red wine, coffee, nuts or beans, then you should probably avoid eating bilberries altogether.<\/span><\/p>\n\n\n\nSome medical experts have concerns about the use of bilberry extract in supplement formulas, as the long term effects of exposure to tannins remain unstudied by medical science. Doctors recommend that pregnant women should avoid eating bilberries and any other foods that are high in tannins. <\/span><\/p>\n\n\n\nThe anthocyanins found in bilberries may also inhibit the effect of chronic medications such as those used in the treatment of cancer, beta-blockers, and antibiotics \u2013 speak to your doctor for more advice.<\/span><\/p>\n\n\n\n\n\n\n\r\n<\/div>