“…In the early twentieth century, lay practitioners in Europe used various peeling formulas, including trichloroacetic acid, salicylic acid, resorcinol, formaldehyde, acetic acid, and phenol [282]. A retrospective claim has been made for the use of phenol peeling for acne scars in 1903 [278,283]. Phenol was also used to treat hypertrophic scars resulting from poison gas burns in WWI [277,284].…”