Aims and Objectives: To investigate the oral health effects of using toothpaste containing granular calcium carbonate (CaG). Materials and Methods: The subjects were adult volunteers. Two kinds of toothpaste, Paste P and Q were used. Paste P contained 13% CaG, which had a mean diameter of 250 µm and a breaking strength of 20 gf. Paste Q had the same formulation without CaG. Study 1 was to evaluate the ability to remove dental plaque by toothpaste with a single use, and it was a crossover study. The subjects were 50 adults. Plaque levels were assessed using the Quigley–Hein Index (QHI). Study 2 was to investigate the effects of CaG in toothpaste on gingival health. The subjects were 60 adults. The subjects used Paste P for 3 days before the baseline assessment. On the baseline assessment, the subjects whose gingival sulci were found to contain CaG were asked to continue using the Paste P for 6 months. The pocket depth, the gingival index (GI), the QHI, and the presence of CaG in the gingival sulci at 1, 3, and 6 months from the baseline were examined. Results: In study 1, the CaG-containing toothpaste produced a significantly lower mean QHI than the control. In study 2, the QHI and GI of the gingival sulci in which CaG was detected were significantly lower than those of the gingival sulci in which CaG was not detected. Conclusion: Toothpaste containing CaG removed greater amounts of plaque and did not have adverse effects on periodontal tissue.