The aim of this study was to re-investigate the anticalculus effects of calcium lactate. To this end calcium lactate was incorporated into experimental toothpastes. Three groups of 20 human volunteers brushed their teeth at least twice daily with three different toothpastes: (1) one containing calcium lactate, (2) one containing calcium lactate plus sodium lauryl sulphate, and (3) a control toothpaste. Plaque accumulation, gingival bleeding and calculus formation were scored at the beginning and at the end of the 3-month experimental period. After the first clinical examination the dentition was professionally cleaned to remove all dental deposits. The use of the calcium lactate containing toothpastes had no significant effects on plaque accumulation and gingival bleeding. However, calculus scores were significantly reduced in the calcium lactate groups at the end of the experiment. The results confirm and extend previous findings that the topical use of calcium lactate reduces calculus formation by, as yet, unexplained mechanisms.