A single-site, randomized clinical trial was designed to determine the efficacy of regular home use of Lumoral® dual-light antibacterial aPDT in periodontitis patients. For the study, 200 patients are randomized to receive non-surgical periodontal treatment (NSPT), including standardized hygiene instructions and electric toothbrush, and scaling and root planing, or NSPT with adjunctive Lumoral® treatment. A complete clinical intraoral examination is conducted in the beginning, at three months, and at six months. This report presents the three-month results of the first 59 consecutive randomized subjects. At three months, bleeding on probing (BoP) was lower in the NSPT+Lumoral®-group than in the NSPT group (p=0.045), and more patients in the NSPT+Lumoral®-group had their BoP below 10% (52% vs. 29%, respectively, p=0.008). Patients in the NSPT+Lumoral®-group improved their oral hygiene by visible-plaque-index (p=0.0002), while the NSPT group showed no statistical improvement as compared to baseline. Both groups significantly reduced the number of deep periodontal pockets, but more patients with a reduction in their deep pocket number were found in the NSPT+Lumoral® group (92% vs. 63%, p=0.01). Patients whose number of deep pockets was reduced by 50% or more were also more frequent in the NSPT+Lumoral®-group (70% vs. 33%, p=0.01). Patients with initially less than ten deep pockets had fewer deep pockets at three-month follow-up in the Lumoral® group (p=0.02). In conclusion, adjunctive use of Lumoral® in NSPT results in improved treatment outcomes at three months post-therapy.