Hypertrophic scars and keloids are difficult to treat and often recur; article evaluated the efficacy and safety of glucocorticoid therapies based on 42 randomized and comparative clinical trials. Treatment included intralesional, local (to the skin) and various technique-assisted administration of glucocorticoids. Corticosteroids alone in the intervention methods significantly improved scar condition (SMD = 1.28; 95% CI: 1.05–1.51; p < 0.05; I2 = 43%). Treatment based on 5-fluorouracil (5-FU) had a similar effect (SMD = 1.15; 95% CI: 0.97–1.34; p < 0.05), and laser methods also brought significant improvement (SMD = 0.99; 95% CI: 0.81–1.16; p < 0.05). Combined techniques (steroids + 5-FU, laser-assisted delivery, microneedling, cryotherapy with corticosteroids) achieved consistently better results than individual methods. According to the GRADE assessment, the certainty of the evidence was low for microneedling and cryotherapy-assisted techniques, moderate for recurrence rates, cosmetic results and adverse effects, and excellent for reduction of scar volume, relief of pain and pruritus. Adverse effects, especially telangiectasia (dilated vessels) and moderate skin atrophy, were temporary and resolved spontaneously. The available data show that the most effective and safest treatment for keloids is intralesional administration of triamcinolone (TAC), and multimodal regimens focused on glucocorticoids remain the basis of proven treatment.