Trichloroacetic acid (TCA) alone or in combination with other agents is the mainstay of medium-depth chemical peels. Indications for medium-depth chemical peels include both medical conditions, such as diffuse photodamage with contiguous actinic keratoses, and cosmetic conditions, such as the aging face and solar lentiginosis. Medium-depth chemical peeling with TCA is relatively simple and is associated with a favorable risk/benefit ratio. However, proper patient selection, with attention to both medical and psychological factors, requires significant experience. The histological basis of the rejuvenating effects of TCA peels is well established, with a consistent correlation between wound depth and TCA concentration. The clinical effects of medium-depth chemical peels are generally gratifying for both patient and physician.