Macrolide immunosuppressant drug that inhibits calcineurin which is used to prevent rejection of transplanted organs (kidney, liver, heart ...) and for treatment of atopic eczema, psoriasis and other autoimmune illnesses (e.g. Arthritis, Lupus, Inflammatory Bowel Disease ...) .Routes of administration: oral for systemic purposes and topical for dermatologic conditions. Systemic administration is approved by various scientific societies and expert panels, (Constantinescu 2014, Götestam-Skorpen 2016, Flint 2016) due to its negligible excretion into breastmilk, the absence of side effects in infants from treated mothers and a low or absent plasma levels in these infants (for details, see info on Tacrolimus). Absorption and bioavailability through skin is even lower than that found by mouth, 30 times lower even after application on 50% of body surface (Draelos 2005 Undre 2009, Gutfreund 2013, EMA2016), therefore milk levels would be expected further lower than after oral ingestion. Do not apply on the breast to prevent ingestion by the infant, otherwise, do it just after a meal and clean the nipple thoroughly with water before the next feed.Local application on the nipple of creams, gels and other products containing paraffin (mineral oil) should better be avoid to keep the infant off from absorption (Noti 2003, Concin 2008).