In order to investigate structures formed by AmB in these complex natural lipid membranes in detail we employed neutron reflection,making use of the large difference in neutron scattering between hydrogen and deuterium isotopes to achieve contrast inside the complex membrane system. Unlike previous structural studies [27,60], we performed the measurements in-situ to follow the effect of extraneously added AmB to better reflect the mode of action against fungal cells (instead of pre-mixing it in the lipid membranes).