## 1 Introduction
It is presented as a way of supporting the treatment of several clinical conditions, namely, treatment of inflammation, pain relief, local anesthesia, treatment of soft tissue mineralization, wound and infection treatment, among others. Iontophoresis is a technique of transdermal drug delivery and is considered to have numerous theoretical advantages when compared to other forms of drug delivery. The main advantage is the fact of being a non-invasive technique that increases the permeability the of skin to ionically charged substances, improving the therapeutic efficacy, avoiding metabolism, and preventing the inconvenience caused by parenteral administration as well as oral administration of drugs, responsible for the absorption by the systemic circulation, reducing the possibility of dosage variation [10; 11]. The possibility of \"programming\" the administration of the ionically charged substances provides a therapeutic framework that enhances patient compliance. Pelotherapy is also a non-invasive technique, however passive, for the application of muds for therapeutic purposes, despite the therapeutic characteristics being empirical because there are no criteria established for the certification of clay products with therapeutic action [12]. The skin route for peloids' local therapeutic action or for peloids' systemic action, provides two routes of penetration, via the pores, sweat glands, sebaceous glands, and hair follicles and via diffusion through the stratum corneum. Considering the general view of pelotherapy, associated with thermalism and electrotherapy (iontophoresis) with physical medicine and rehabilitation, the transdermal delivery of drugs (e.g., diclofenac, corticosteroids or steroids) or clays with therapeutic properties is limited due to the excellent barrier function of the stratum corneum. The main objective of this type of transfer systems is to obtain optimum therapeutic control, which results in strong patient benefits and low safety-related risk, especially regarding the potential and degree of toxicity arising from ion exchange. In physical rehabilitation, the treatment of patients with pain associated with rheumatic disorders gets excellent relevance, using the afore-mentioned action mechanisms that can contribute to the treatment and relief of pain and improvement of the functional performance of the joints. In this context, electrotherapy (iontophoresis) and pelotherapy can be included as treatments for pain relief and improvement of motor functionalities: electrotherapy, by transcutaneous electrical nerve stimulation (TENS) with transdermal drug passage, and pelotherapy by heat therapy and transdermal passage of essential elements of peloids. Since the challenge for pelotherapy and electrotherapy (iontophoresis), as therapeutic methods, is in the passage of some ionic specimens, the study of the use of iontophoresis in therapeutic peloids is considered relevant, involving the application of an electric potential (voltage) between the peloid and the skin, accelerating the transfer of the clay ions and conferring on this method utility in the transfer efficiency of essential elements of the clay while analgesic, antiseptic or anti-inflammatory agent (Table 1). The next sections will detail the health and wellbeing significance of pelotherapy and electotherapy, the skin's role in effective topical applications of medicines or other substances, transdermal drug delivery, as an innovative method, for delivering therapeutic or aesthetic substances, and the main inhibitors and promotors of a good dermal permeation. Section 4 will present the importance of pelotherapy and electotherapy in the physical rehabilitation field.