NAF Devils Relief. Help to preserve your horses joint health with NAF Devils Relief. Combining a powerful mix of herbal tinctures and Devil\\\'s Claw, Devils Relief helps to ease stiffness and limited flexibility. Due to the bitter action of the formulation, Devils Relief can also help to stimulate the digestive system and can be fed to all range of horses and ponies with the exception of pregnant mares. Devils Relief contains devil\\\'s claw which is an FEI prohibited substance.