Background This study aimed to determine the effect of the consumption of a probiotic on the clinical characteristics of Candida-associated denture stomatitis (DS) and to determine the impact of a protocol of self-care measures in oral/prosthetic hygiene in institutionalized elders that wear removable prostheses (RP). The current treatment for DS is the systemic use of antifungals, as well as the replacement of these devices together with oral/prosthetic hygiene instructions. Methods This study was a randomized, controlled and triple-blind trial. Thirty-six elders presenting DS of different severity and who carried RP consumed milk with/without the probiotic L. rhamnosus SP1. The prevalence and severity of DS and prevalence of Candida were determined and all participants/caregivers were trained in oral/prosthetic hygiene. Results In both groups a decrease in the prevalence of DS was observed (P < 0.05) but only the group that consumed probiotic throughout the trial had a significant reduction in the severity of DS and reduced Candida counts (P < 0.05). Educational instruction in oral/prosthetic hygiene was relevant for the participants, regarding the prevalence of this lesion. Conclusions The frequent consumption of Lactobacillus rhamnosus SP1 and the establishment of a protocol of oral/prosthetic hygiene drastically reduced the severity of DS in institutionalized elders who wore RP.