Proanthocyanidins, also named condensed tannins, are the result of flavanols condensation. Oligomers and polymers of proanthocyanidins can widely be found in the plant kingdom, as in fruits and berries, seeds, flowers, and leaves. They have a putative role as antioxidants, and they affect the inflammatory process via calcium-dependent release of nitric oxide and protect against H(2)O(2)-induced lipid peroxidation. They also demonstrated a role in cardiovascular diseases via vessel relaxation and LDL oxidation inhibition. These condensed tannins have also shown activities that improve diabetic complications, such as neuropathy, retinopathy, or nephropathy, including a decrease in serum glucose and advanced glycation end products. Furthermore, proanthocyanidins have evidenced anticancer properties by mitigating tumor development through induction of apoptosis or inhibition of cell proliferation. Finally, they are able to produce antiadhesive actions against bacteria in urinary and dental infections, including Escherichia coli and Streptococcus mutans. Hence, proanthocyanidins are considered as beneficial molecules in preventing or treating many diseases and pathological conditions. Therefore, finding out more about condensed tannins bioavailability, and understanding the regulatory genes and pathways involved in their effects should be aimed in future research.