Considerable recent research has explored therapeutic applications of oligomeric proanthocyanidin complexes (OPCs), naturally occurring plant metabolites widely available in fruits, vegetables, nuts, seeds, flowers, and bark. OPCs are primarily known for their antioxidant activity. However, these compounds have also been reported to demonstrate antibacterial, antiviral, anticarcinogenic, anti-inflammatory, anti-allergic, and vasodilatory actions. In addition, they have been found to inhibit lipid peroxidation, platelet aggregation, capillary permeability and fragility, and to affect enzyme systems including phospholipase A2, cyclooxygenase, and lipoxygenase. Based on these reported findings, OPCs may be a useful component in the treatment of a number of conditions.