Topical medication, also known as topical medication, refers to medication applied directly to the surface of the skin. An important feature of dermatology treatment is the importance of topical medication. I often say to patients that they should not take medication if they can apply it; they should not take injections if they can take medication; they should not take intravenous medication if they can inject it. The reason is that most dermatological diseases develop in the skin, and topical drugs reach the affected area directly, without affecting other normal skin and other organs of the body, so the therapeutic effect is large, with few side effects and little or no effect on the whole body. Moreover, topical medications are mostly cheaper than oral medications. Therefore topical medication is the preferred method for most skin diseases. Systemic treatment is usually administered only when topical treatment is not effective. Topical medications are usually creams or ointments applied topically to the lesion area for treatment. Although topical medications are commonly used, doctors may not always be careful to explain the dosage during a patient’s visit. As a result, patients are at a loss as to what to do with their medications. The following is an example of the “fingertip unit” to control the amount of topical medication used in the treatment of psoriasis, using carbatriol ointment. The fingertip unit is the basis for proper topical treatment. The fingertip unit is a simple, individualized measurement that shows the amount of cream or ointment to be applied to a single lesion. A fingertip unit is the amount of ointment or cream that is squeezed out to cover the first interphalangeal joint from the tip of your index finger and is equivalent to one gram of ointment – see the chart below. One fingertip unit is enough to cover an area the size of two palms on the body surface. Therefore two fingertip units are sufficient to coat four palm-sized areas of skin. One fingertip unit will apply approximately 2% of the body surface area.