PurposeThis clinical trial aimed to evaluate the use of a mouthwash and a dentifrice containing antimicrobial phthalocyanine derivative (APD) on the reduction of clinical symptoms in COVID-19 patients.MethodsThis randomized triple-blinded clinical trial enrolled 500 patients aged 18 years or older submitted to COVID-19 test by nasopharyngeal swab RT-qPCR in a reference center for the diagnosis of COVID-19, had no clinical contraindications to perform mouthwash and gargle, and had access to cell phone with communication application. Patients were randomly assigned (1:1) to use a mouthwash, and a dentifrice both containing antimicrobial phthalocyanine derivative (APD Group) or Non-APD (Control Group). All participants were instructed to floss twice a day, toothbrushing during 2 minutes/three times a day, and for gargling/rising (5ml) during 1 minute/three times a day for 7 days. An online questionnaire was sent to collect the clinical symptoms of COVID-19 in three times: T0 (baseline - before using the oral hygiene products); T3 (three days after); and T7 (seven days after). The investigators, patients, and outcomes assessor were blinded to group assignment. Mann-Whitney test, Chi-Square test, Exact Fisher test, and Cochran’s test were used according to the nature of the variables studied, with the level of significance set at P < 0.05.ResultsNo statistically significant difference was found in the prevalence of symptoms between the groups at baseline. A statistically significant reduction of clinical symptoms was found in the Control Group (fatigue, shortness of breath, hoarse voice, sore throat, nasal congestion, and chest pain) and in APD Group (cough, fatigue, shortness of breath, hyposmia/anosmia, dysgeusia, hoarse voice, sore throat, nasal congestion, chest pain, diarrhea and irritability/confusion) during the follow-up period. There were statistically significant differences with a higher symptoms’ prevalence for the Control Group at T3 and T7. Dysgeusia, sore throat, irritability/confusion was less prevalent at the APD Group at T3, and shortness of breath, hyposmia/anosmia, dysgeusia, hoarse voice, sore throat, diarrhea, and irritability/confusion were more prevalent in the Control Group at T7.ConclusionsBased on methodology, the results demonstrated that the regular use of mouthwash and dentifrice containing APD had a positive impact on the clinical symptoms reported by COVID-19 patients.