Trial design: The study is a randomized clinical placebo-controlled trial in parallel groups 1:1 allocation ratio. Methods: 30 patients with erosive oral lichen planus were randomly assigned to receive either platelet lysate mucoadhesive gel or placebo vehicle gel 3 times per day for 4 weeks. Outcomes: Assessment of outcomes included a visual analog scale (VAS) for pain as a primary outcome, and the secondary outcomes included improvement in the clinical picture according to thongprasom sign score and any side effects of treatment. Results: results had shown a significant reduction of both pain and clinical scores in both groups at 2, 3, and 4 weeks and at 3 months of follow-up and a significant difference in pain and clinical scores between the intervention and control group at each visit as well as at 3 months follow up in which the intervention had greater pain reduction and clinical improvement. Conclusion: Platelet lysate mucoadhesive gel is a promising material for managing erosive OLP and could be considered a suitable, safe, and easy alternative to other hemo-derived products. However, further larger randomized controlled trials are recommended.