In the synergetic approach to brain-mind interaction the dimension of stability and instability is of central importance for the understanding of cognitive phenomena. Instability is the basic characteristic of the process of self-organized order formation and stability is a possible result. In this paper synergetic concepts are used to reanalyse the well-known phenomena of cognitive multistability and suggestion. On the basis of existing experimental data a close relation between these seemingly very divergent phenomena is postulated. The rate of apparent change of perceptual multistability is assumed to be an indicator for the degree of innersystemic fluctuation in the brain. This degree of fluctuation is critical for the ability of the system to respond to minimal external influences and the rate of apparent change is therefore hypothesized to be correlated with suggestibility. Experiments are outlined which strongly support this hypothesis. At the end as a consequence some speculations about the relevance of these ideas and results for the field of psychosomatic phenomena are discussed.