Lac resin, also known as shellac, is a natural resin secreted by the lac insect (Kerria lacca). Its use in the treatment of scratches and abrasions is primarily rooted in traditional and folk medicine, particularly in South Asia. Historically, lac resin has been applied topically as a protective coating or dressing for minor wounds and abrasions. Its film-forming properties create a physical barrier that can help protect the wound from external contaminants and may promote a moist wound environment, which is generally favorable for healing. Additionally, shellac has been used in Ayurvedic medicine for its purported antimicrobial and healing properties.

However, the scientific evidence supporting the efficacy of lac resin in wound healing or for the treatment of scratches and abrasions is limited. There are few, if any, robust clinical studies that directly evaluate its effectiveness or safety for this purpose. Most available information is anecdotal or based on the resin's physical properties rather than pharmacological action. Modern medicine does not typically recommend lac resin for wound care, given the availability of better-studied and more effective wound dressings and topical agents. Thus, while the use of lac resin for scratches and abrasions is justified by tradition, it lacks substantial scientific validation.