Abstract
ABSTRACT: A drug is defined as a medicine or substance that causes a physiologic effect on the body. A drug can be administered by various routes including oral, intravenous, intramuscular, topical, transdermal, or subcutaneous. The purpose of this section is to focus on common drugs used in dermatology, the drugs' mechanisms of action, their indications and function, and adverse effects. The focus of this article is methotrexate and its usefulness in treating psoriasis as well as its adverse effects.