PURPOSE: To determine the effect of short-term 4 mg/mL dexamethasone solution treatment in diabetic macular edema (DME). PATIENTS AND METHODS: Twenty-seven pseudophakic diabetic patients with visual impairment caused by DME were randomized to receive 0.01 mL (40 µg), 0.03 mL (120 µg) or 0.05 mL (200 µg) intravitreal dexamethasone solution. Eyes were evaluated in terms of macular thickness, best-corrected visual acuity (BCVA) and intraocular pressure (IOP) at 3, 7 and 28 days after injection (D). RESULTS: There was a significant reduction in macular thickness between D0 and D3 for all groups (0.01 mL - P=0.008, 0.03 mL - P=0.038, and 0.05 mL - P=0.008). Between D0 and D7, a significant reduction in macular thickness was observed in 0.01 mL and 0.05 mL groups (0.01 mL - P=0.013 and 0.05 mL - P=0.021). Between D0 and D28, no significant reduction of macular thickness was observed for any group. Between D0 and D3, a significant improvement in BCVA in the 0.03 mL group (P=0.028) was observed. Between D0 and D7, a significant improvement in BCVA was observed in 0.01 mL and 0.03 mL groups (0.01 mL - P=0.018 and 0.03 mL - P=0.027). Between D0 and D28, a significant improvement in BCVA was observed for the 0.01 mL group (P=0.017). No significant differences in IOP measurements were observed for any group. Safety analysis revealed no serious ocular or systemic events. CONCLUSION AND RELEVANCE: Intravitreal dexamethasone solution is effective in reducing macular thickness secondary to DME in the short-term. Improvement in short-term visual acuity was observed. Although DME requires long-term treatment, it may be a low cost therapeutic option used in specific short-term situations.Trial registration: NCT03608839 (http://www.clinicaltrials.gov).