IBD is an incurable chronic, relapsing condition of unknown aetiology. Its frequency has increased markedly across the world in recent years with the highest prevalence reported in Europe (322/100,000 population for CD; 505/100,000 for UC). A marked increased incidence has been seen in children especially in the Northern Hemisphere and largely due to an increase in Crohn's disease. Up to 25% of IBD starts in childhood or adolescence.