Products derived from the black chokeberry, Aronia melanocarpa, are claimed to be beneficial in disorders or diseases associated with oxidative stress. The claims are based on evidence from in vitro studies and animal experiments. The active principle - a mixture of procyanidins, anthocyanins and phenolic acids - constitutes one of the most potent natural antioxidants. We carried out a systematic review of the quality of the clinical trials on chokeberry products that had been published up to December 2009, and used conventionally established criteria to assess the strength of the evidence for their clinical effectiveness. Thirteen studies were identified. The quality of most of the trials and, correspondingly, the evidence of effectiveness for Aronia products is poor. Though laboratory and clinical data indicate that chokeberry products may well be useful as “functional food” for disorders or diseases related to oxidative stress, these promising indications need to be confirmed in more rigorous studies before putative therapeutic uses can be confidently recommended for chokeberry products.