Liquid Gaviscon and Gaviscon Advance are established reflux suppressant formulations. This study describes the use of echo-planar magnetic resonance imaging (EPI) to visualise non-invasively intragastric alginate rafts of Liquid Gaviscon and Gaviscon Advance in healthy subjects. Secondly, the feasibility of using relaxation rate (T2−1) measurements to monitor changes in the physicochemical properties of the rafts in-vivo is evaluated. Six subjects ingested 500 mL of a liquid meal and received a single dose of 20 mL Liquid Gaviscon or 10 mL Gaviscon Advance on 2 separate visits each and were imaged every 15 min. An alginate raft was observed in the stomach for all subjects and both treatments. The raft was observed to consist of a few large fragments on the majority of the scans for both products. At t = 60 min a raft was still present in all cases. Three-dimensional volume reconstructions showed, for the first time, the spatial distribution of the rafts within the gastric lumen. The T2−1 data showed potential for assessment of dynamic changes in the physicochemical properties of the alginate rafts in-vivo. We conclude that EPI shows great potential in assessing alginate rafts formation in-vivo.