SB-215505 is a drug which acts as a potent and selective antagonist at the serotonin 5-HT<sub>2B</sub> receptor, with good selectivity over the related 5-HT<sub>2A</sub> and 5-HT<sub>2C</sub> receptors. It is used in scientific research into the function of the 5-HT<sub>2</sub> family of receptors, especially to study the role of 5-HT<sub>2B</sub> receptors in the heart, and to distinguish 5-HT<sub>2B</sub>-mediated responses from those produced by 5-HT<sub>2A</sub> or 5-HT<sub>2C</sub>.