- Intestinal permeability is a key feature of intestinal barrier function. Altered intestinal permeability is described in many chronic diseases and may be a risk factor for disease development and a target for emerging therapeutics. Thus, reliable and sensitive methods to measure intestinal permeability in both the clinical and preclinical setting are needed. There is currently a large array of tests to choose from, each with advantages and disadvantages. When possible, a combination of methods should be used. The choice of tests should be based on a deep understanding of intestinal barrier physiology and the recognition of their limitations. This mini-review will highlight the advantages and limitations associated with intestinal permeability tests and will identify current problems in the field and how they can be addressed in the future.