The aims of the present study were to register the effect of toothbrushing with chlorhexidine gel for 51 weeks and compare the effect of two hygiene regimens, one with continuous use of chlorhexidine gel for toothbrushing twice a day and the other in which ordinary toothpaste was substituted for chlorhexidine 1 week every third week. The total number of participating patients was 152 institutionalized elderly, mean age 76.2 years, Gingival Index according to Löe‐Silness and Plaque Index according to Bay‐Ainamo were registered 12 times during the study. The long‐term effect of Toothbrushing with chlorhexidine gel was equal for the two hygiene regimens. The incidence of side effects was surprising small. Moderate discolouration of teeth occurred with equal distribution in both