Gastrointestinal (GI) mucus is a biologically complex hydrogel that acts as a partially permeable barrier between the contents of the GI tract and the mucosal epithelial lining. Its structural integrity is essential for the lubrication of the tract thereby aiding smooth transit of contents, and the protection of the epithelium from pathogens that seek to colonise and invade. Understanding its physical response to drugs and the microbiome is essential for treating many gastrointestinal infectious diseases. Given this, an in vitro model of a GI mucus-on-a-chip has been developed with integrated electronics to monitor the barrier properties of mucus hydrogels. Its application for investigating the effect of drugs and biofilm formation on the mucus structure is validated using rheological techniques, confocal microscopy, and electrochemical impedance spectroscopy (EIS).