The inflammatory bowel diseases, namely Crohn disease and ulcerative colitis, increasingly matter, especially in industrial nations as well as in emerging countries. In the USA and Europe there are already 3.6 million people affected by either one of the above mentioned diseases. Crohn disease is a transmural chronically inflammation of the mucous membrane, which can discontinuously occur within the entire gastrointestinal tract. On the contrary, the inflammation caused by ulcerative disease is usually limited to the mucosa and is located continuously, ascending from the Anus to at most the terminal ileum. The road to the initial diagnosis is a long one, as those diseases appear insidiously and medical advice is sought only if the discomfort is very bad. Until today there is no causal therapy, the therapy is still purely symptomatic. In the context of this thesis a brief overview of the discovery of Crohn disease and ulcerative colitis will be given. In greater detail the epidemiology will be discussed and the complex interaction of genetics, environment and microbiome regarding the partly unresolved etiopathogenetic will be commented. Additionally the differences regarding diagnostic, disease course and types of disorders of the two diseases are being highlighted. The focus of this thesis is on the medical therapy with their groups of active substances. Two therapeutic strategies as well as the stepwise approach will be presented and finally the therapy procedures for pregnant women and children are investigated.