Objective To investigate the effectiveness of insulin dilutions for moist dressing in treating skin injury caused by extravasation of concentrated potassium chloride. Methods A total of 23 patients with extravasation injury following intravenous injection of concentrated potassium chloride were treated with a moist dressing using insulin dilution (20 U of insulin injection added to 250 mL of 0.9% sodium chloride injection). The effects of the dressing with topical insulin were observed. Results In the first case, necrosis occurred at the extravasation site. After 6 days of insulin therapy, the skin injury healed within 10 days. The remaining 22 patients had the moist dressing duration of 3.00（2.00，4.00） days and the healing time of 4.00（2.00，5.00） days. There were no statistically significant differences in the extravasation area, pain intensity, or healing time between patients who underwent moist dressing within 24 hours or after 24 hours of extravasation, and between patients with or without diabetes (all P>0.05). In the 2%, 4%, and 6% potassium chloride concentration groups, pain intensity on the third day and healing time showed significant differences (all P<0.05). Conclusion Moist dressing with insulin dilutions is effective and safe for treating skin injury caused by extravasation of potassium chloride.