We are fortunate to have many effective treatments for inflammatory bowel disease (IBD). Most of our treatments work by modulating or suppressing the immune system, which is overactive in patients with IBD. While our treatments can often induce a remission and maintain a remission, they can also be associated with side effects. Close monitoring of our patients on these medications allows us to prevent complications of treatment. Mesalamine drugs, often used to treat ulcerative colitis, can rarely be associated with damage to the kidneys. Due to this rare, but potentially serious side effect, all patients taking this class of drug should have their kidney function tested every 6–12 months. Immunomodulators, such as azathioprine or 6-mercaptopurine, can cause a drop in one’s blood counts and an increase in liver enzymes. As a patient begins these medications, frequent monitoring of blood counts and liver enzymes is needed. Once a stable dose is established, blood tests are often monitored every few months indefinitely. Likewise, patients on methotrexate also require frequent blood work to monitor for drops in blood counts or signs of liver inflammation. Patients on biologic therapies (such as infliximab, adalimumab, golimumab, certolizumab, natalizumab, and vedolizumab) also require routine blood work, although typically only every 6–12 months. For several biologic therapies and immunomodulators, we are able to monitor drug levels which allow us to optimize an individual’s treatment or assess for intolerance to a given drug. Routine blood work helps monitor tolerance of therapy and also can provide clues to a patient’s disease state. Although frequent blood tests may seem inconvenient or uncomfortable, it is important to remember that proactive care is much more effective than reactive care, particularly for our patients with IBD.