Biological therapy of anti-TNF represents an essential breakthrough in strategy of therapy of idiopathic bowel inflammations. This therapy is not causal but symptomatic and therefore a large number of questions are emerging. The big problem is secondary resistance that reaches 50 % during cyclic therapy. Manipulation with dosage regimes could be helpful and benefits and risks of combination with immunosuppressives are discussed. Opinion development is also evident in evaluation of risks of biological therapy in pregnancy.