Given the substantial degree of inter-individual variability in treatment responses in patients with inflammatory bowel disease (IBD), treatment optimization is warranted. We provide an overview of pharmacogenetic variants that can affect the efficacy or toxicity of drugs commonly used for IBD. We used The Danish Register of Medical Product Statistics to collect information about medical treatment from 2000 – 2020. The most used drugs were Methotrexate, Azathioprine, Mesala-zine and Sulfasalazine. Of these Azathioprine, Mesalazine and Sulfasalazine has pharmaco-genetic recommendation guidelines and/or FDA annotations. About 16.853 Danish individuals (~ 842 individuals each year) are potential carriers of a genetic variant with pharmacogenetic dosing guidelines. Moreover, up to 27.044 Danish individuals (~1352 individuals each year) have potential risk of developing immunogenicity. This study showed the possibilities of pharmacogenetic testing as a supportive clinical decision tool to optimize treatment and minimize the risk of e.g., serious adverse effects, remission and other serious complications.