Cinnamtannin B-1 is a naturally occurring A-type proanthocyanidins, available in a limited number of plants, including C. zeylanicum and L. nobilis, that exhibit a large number of cellular actions mostly derived from its antioxidant activity, including antitumoral activity mediated by a selective pro-apoptotic action in a number of tumoral cell lines associated with a remarkable antiapoptotic activity in normal cells. In addition, cinnamtannin B-1 shows antithrombotic actions through inhibition of platelets' endogenous ROS generation, Ca2 mobilization and subsequently aggregation. This has been reported to be especially relevant in platelets from diabetic patients where cinnamtannin B-1 reverses both platelet hypersensitivity and hyperactivity. Considering the large number of cellular effects of cinnamtannin B-1, this compound might be further investigated for the development of therapeutic strategies based on its use for thrombotic disorders or certain types of cancer. Cinnamtannin B-1 is a potent antioxidant and protective agent against oxidative stress and apoptosis in human platelets. Cinnamtannin B-1 is a Cox-2 (cyclooxygenase-2) inhibitor. Cinnamtannin B1 was a potent cancer cell proliferation inhibitor and a good intracellular antioxidant.