PURPOSE: A remedy and preventive for contact dermatitis, comprising a nandin as an active ingredient.

CONSTITUTION: The titled remedy and preventive containing powder of bark, leaf, root, trunk or branch, or fruit of Nandina domestica THUNB, preferably an extract from it. It is useful for remedying and preventing humit tetter, erythema swelling, vesicula, etc., applicable in the dosage form capable of being administered to the skin, such as plaster, lotion, tincture, etc. When plaster consiting of pressure-sensitive adhesive substance of high polymer is blended with a nandin, the plaster itself is used not only as a remedy for contact dermatitis, but also as a plaster base which keeps any of other various drugs without decomposing the drug when it is blended with the drug.