Previous studies have found a link between emotion processing deficits and medically unexplained physical symptoms (MUS). The majority of previous studies have used self-report measures of emotional processing, with the majority focusing on alexithymia, and have produced inconsistent and contradictory results. In the present study, we investigated the role of emotion-processing deficits in MUS by assessing emotion regulation performance and the effects of performance on ego depletion. Participants with high or low levels of self-reported MUS watched emotion-evoking videos under instructions to allow or suppress their emotional reactions, and then performed an anagram task to measure their effort and perseverance. Contrary to the research with self-report measures, experimental analysis of emotion-processing revealed that MUS is correlated with the inability to regulate negative emotions. Unexpected self-regulatory tendencies of the participants with high symptom levels were discussed.