These national clinical guidelines outlining the screening, prophylaxis and critical information required prior to initiating anti-TNF-alpha treatment have been approved by the Danish Society for Gastroenterology. Anti-TNF-alpha therapy is widely used in gastroenterology (for inflammatory bowel disease), rheumatology (for rheumatoid arthritis, psoriatic arthritis and spondyloarthropathies) and dermatology (for psoriasis). With this background, the Danish Society for Gastroenterology established a group of experts to assess evidence for actions recommended before treatment with anti-TNF-alpha agents. Screening should take place for both active tuberculosis and latent tuberculosis. Screening must evaluate the risk of hepatitis B exposure/infection and that of other viral infections such as human immunodeficiency virus (HIV) and varicella zoster virus (VZV). The assessment should include a history of previous malignancies (cases of malignant disease within 5 years of anti-TNF-alpha treatment should be carefully considered). The physical examination should include lung/heart auscultation and lymph node examination, and the paraclinical investigations should include chest X-rays and laboratory tests, including an interferon gamma release assay, a hepatitis B test, an HIV test and, when prior VZV infection is uncertain, a VZV antibody test. Prophylaxis: Isoniazid should be administered in cases of suspected latent TB infection. Antiviral treatment is recommended in HBsAg-positive patients at the start of anti-TNF-alpha treatment. Before anti-TNF-alpha therapy, vaccination with 23-valent pneumococcal vaccine is recommended, and HBV vaccination may be considered in seronegative patients. Annual vaccination against seasonal influenza is recommended. Human papilloma virus vaccination should be administered in accordance with the guidelines of the National Board of Health of Denmark. In patients without a prior VZV infection, VZV vaccination may be considered. Information for patients: Anti-TNF-alpha treatment results in a generally increased risk of infection and latent tuberculosis flare-up. Women are advised to comply with the national guidelines for screening for cervical cancer, and their HPV immunisation status should be clarified. An increased risk of lymphoma with biological therapy in combination with thiopurines should be mentioned. Patients are advised to seek medical advice in case of herpes zoster infection.