Hello, 5-Fluorouracil (5-FU) is indeed an effective treatment option for certain types of scars, particularly hypertrophic scars and keloids. It works by inhibiting fibroblast proliferation, which can help reduce the size and appearance of these scars. Additionally, 5-FU is often combined with other treatments, such as corticosteroids or laser therapy, to enhance its efficacy. The reason not all doctors use 5-FU routinely after surgeries may vary. Some factors include: Specificity of Scarring: 5-FU is primarily effective for specific types of scars and may not be suitable for all patients or scar types. Treatment Protocols: Different physicians may have varying protocols based on their experience, patient demographics, or preference for other established treatments like silicone sheets, laser therapy, or steroid injections. Side Effects and Reactions: While 5-FU does not typically thin the skin like some other treatments, it can still cause local irritation, redness, or discomfort, which may influence its use depending on patient tolerance. Availability and Cost: The accessibility and cost of 5-FU treatment can also be a consideration, as not all clinics may have the resources to provide it. Ultimately, the choice of scar treatment is tailored to the individual, considering the type of scar, patient history, and potential benefits versus side effects. It’s always best to discuss with a dermatologist to determine the most appropriate treatment for your specific needs. If you have further questions or would like to explore this treatment option, I recommend consulting with a dermatologist who can provide personalized advice based on your situation. Best regards,