The polypeptide hormone, gastrin, is known to promote both the in vitro and in vivo growth of human gastric cancer. This proliferative activity has been shown to be mediated by high affinity, membrane-associated receptors. This has led to the development of agents with the ability to antagonise gastrin receptor binding, which have been evaluated for their potential clinical value. Other anti-gastrin therapies have been investigated. As gastrin may act as an autocrine mediator of gastric tumor cell proliferation, anti-secretory agents have been evaluated, as have agents which induce the production of neutralising anti-gastrin antibodies in situ.