A modified barium swallow study (MBSS) also referred to as a videofluoroscopic swallow study is an instrumental assessment of swallowing function. The x-ray machine will allow visualization of the structures of the mouth and throat as you are eating and drinking. Barium, a white radiopaque paste, is added to food and liquids to allow them to be seen on the x-ray. A speech-language pathologist (SLP) may recommend a MBSS get more information about what may be contributing to any swallowing difficulty you may be experiencing and identify if food or liquid is being aspirated (going into the airway) instead of the esophagus. The primary purpose of the MBSS is to determine what is not working with the swallowing mechanism resulting in swallowing issues and develop an appropriate treatment plan.