The adsorbent layer system is especially suitable for the biological evaluation of different compounds and trace elements as well. Present experiments showed that formaldehyde (HCHO) molecules participate in the antibiotic activity of Cu (II) ion, an „old antibiotic”. The elimination of HCHO from the chromatographic spots (e.g. by reduction or capturing) resulted in a characteristic decrease of the antibiotic effect of trace elements. The trace elements are HCHO carriers and generate a double effect (first step: deprivation of HCHO as also biological effect; second step: release of HCHO with big killing activity). These features offer good opportunities for influencing fundamental biochemical pathways. It has been established that the trace elements (mainly transition metal ions as e.g. Ni(II) ion) always generate quadruple, bioequivalent, specific immune-stimulating activity in plants with a non-linear dose-response. HCHO and its reaction products (mainly O3) are responsible also for this latter activity.