Background/Aims: Adverse events in anti-TNF treatment can be divided into allergic reactions with an acute and delayed onset, infectious complications in relation to the underlying disease, and without. Last but not least, there is the unresolved question of tumor induction and propagation. All of these may account for morbidity and eventually mortality. Methods: Literature-based review to update current knowledge about safety and adverse events of TNF blockers. Results: Major drawbacks are infectious complications with the use of anti-TNF antibodies. The risk is increased in inflammatory bowel disease in general and in the perioperative setting of Crohn's disease patients. The number of tuberculosis cases has decreased since meticulous testing prior to treatment start is mandatory. An excess mortality that has been reported from referral centers is neither documented in randomized controlled trials nor in real-life settings. Regarding malignancies, lymphoma and skin cancer are a concern. The incidence of lymphoma may be raised, but this has also been debated with the use of thiopurines. Skin cancer, especially melanoma, is more common in inflammatory bowel disease and may be associated with the use of biologics. Overall, most studies do not address the influence of active inflammation or co-administration of other drugs. Hence, the risk attributable to TNF blockers alone is currently ill-defined. Conclusion: Treatment with anti-TNF antibodies is an option with substantial risks. Most problems can be prevented by thorough workup of the patient.