Galectin-1 (GAL1), an animal lectin with a carbohydrate recognition domain, is known for its roles in cancer, tumor progression, as well as obesity and related complications. Here, we investigated the anti-obesity effect of lactobionic acid (LBA), a GAL1 inhibitor, both in vitro and in vivo. LBA treatment significantly reduced lipogenic capacity of both 3T3-L1 and HIB1B adipocytes through down-regulation of major adipogenic transcription factors at both mRNA and protein levels. Moreover, oral administration and intraperitoneal injection of LBA in Sprague Dawley male rats fed a high fat diet caused marked reduction of body weight gain as well as improvement of related metabolic parameters. Important lipogenic transcription factors were also down-regulated in LBA-treated rats, resulting in attenuated lipogenesis and fat accumulation. Collectively, pharmaceutical targeting of GAL1 using LBA would be a novel therapeutic approach for the treatment of obesity. (C) 2015 Elsevier Inc. All rights reserved.