Copper plays a key role in converting iron into its active form, mobilizing it from the stores and incorporating it into the red blood cells. An iron deficiency that does not improve despite sufficient intake often has a silent copper deficiency in the background. In the world of planetary associations, copper belongs to Venus – the principle of connection and the ability to relate. The fact that it is precisely this principle that makes iron, the metal of Mars, complete in the first place is one of the most beautiful correspondences between ancient symbolism and modern biochemistry.