This study describes a case of a salivary calculus which contained the limb of a shrimp. Pathological findings seemed to show a stratiform structure of calculus around the foreign body at the center. However, when the cut surface of the salivary calculus was examined by a scanning electron microscope, it was suspected that the origin of the calculus was in another area next to the foreign body. As a result, it became clear that the foreign body was not the core, but that the core of the salivary calculus was somewhere else, and that the earlier foreign body theory needed to be reconsidered. As to the foreign body, the patient remembered eating a shrimp, which was probably the foreign body in question. The findings obtained from the analysis of other shrimp limb specimens were structurally similar. Therefore the suspicion that the foreign body was indeed the limb of a shrimp was increased.