A patch for transdermal therapy comprising at least one layer of sheet material (10) for adhesive attachment to the skin of a user, particulate material (11; 11a; 16) including particulate copper or an alloy thereof provided on the surface of said layer of sheet material presented to the skin of the user in use, and, at least one magnet (13; 13a) disposed on the opposite surface of said layer of sheet material. There is also disclosed a patch for transdermal therapy comprising at least one layer (10) of sheet material for adhesive attachment to the skin of a user, said layer (10) carrying, in association with one another, particulate copper or an alloy thereof (11; 11a) together with at least one magnet (13; 13a), a peelable carrier sheet (12) upon which the patch is mounted by way of the adhesive surface of said layer (10) of sheet material, and a separate tab (19) of carrier sheet material peelably adhesively secured to a peripheral region of said first layer (10) of sheet material whereby said tab (19) can remain in place on said layer (10) of sheet material when the patch is peeled from the carrier sheet (12) to facilitate handling of the patch prior to said tab (19) being peeled from said layer (10) when the layer is applied to the skin of the user.