In terms of gastrointestinal diseases, the pharmaceutical industry is having to adapt in the face of great success (e.g. anti-ulcer drugs), continued failure (e.g. cancer therapy) and increasing commercial pressures. Whilst success is evident by the presence of four anti-ulcer agents in the top 25 best-selling drugs, the GI tract remains the major site of cancer, a disease where almost no progress in drug treatment has occurred since the discovery of anti-metabolites. In addition to being a major therapeutic target, the GI tract is also the principal route of drug administration with some one hundred billion unit dosages being ingested per year. Not surprisingly, therefore, the gut reigns supreme as a site of minor side-effects. More serious adverse reactions are also common and those associated with anti-proliferative and anti-arthritic drugs can be life-threatening. Thus an agent to combat adverse GI reactions represents a drug development opportunity in itself. In terms of primary diseases of the gut, the pharmaceutical industry is having to adapt to the uncertainties inherent in developing drugs in markets which are poorly defined because of the absence of effective treatments. Foremost amongst these are neoplastic and inflammatory diseases. Although these represent formidable targets, clinical needs and consequently commercial success would far outweight any gains from developing another generation of anti-ulcer drugs to compete with existing anti-secretory agents.