This paper presents a case report of indoor Stachybotrys toxins in Germany. In the summer of 2000, heavy rainfall and a leakage of the gutter system of an appartement house in Munich, Germany, caused a severe water damage in one of the appartments. The appartment was at that time occupied by two of the authors (ES, EU). A wall (covered with wallpaper) in one room in particular was most strongly affected, about 6-8 m(2) of the wallpaper became very wet. Large parts of this wet wallpaper were within days infested by multiple circumscribed round, grey-black colonies (0.5-5 cm in diameter) of presumtiveStachybotrys spp.. At the same time, the air in this room became very damp and oppressive. Several persons reported burning sensations on the mucous membranes of the eye, nose, and larynx, followed by headache symptoms, as soon as a few minutes after they had entered this room. Inadvertent skin contact with one of the fungal colonies by one person resulted in burning sensations immediately, but symptoms disappeared after thorough rinsing of the skin with water. The infested room was evacuated, and samples were taken from the wet wallpaper at areas (1) in the center of the most heavy fungal colony growth, (2) several cm away from colony growth, and (3) from locations which were wet but about 1 m away from visible colony growth. The samples were extracted with methanol, the extract diluted with buffer solution and analysed by competitive enzyme immunoassay (EIA) for roridin A. Due to cross-reactivity, this EIA detects several macrocyclic trichothecenes produced byStachybotrys spp.. Heavily infected pieces of wallpaper were strongly contaminated with toxins, with maximum concentrations of 1.1 microgram per cm(2) (Roridin A equivalents). Wet but visibly not infected samples of wallpaper were negative in the EIA. Considering a EIA cross-reactivity of satratoxin H (the major Stachybotrys-toxin) of 15%, the actual maximum toxin concentration would correspond to 6 microgram of satratoxin H per cm(2). As far as we know, this is the first documented case of indoor Stachybotrys toxins in Germany. The toxin concentration by far exceeds the minimum toxin level required for skin toxicity, and was considered as unhealthy. Health authorities in Munich were informed but were unable to provide assistance, probably because awareness of the importance and the possible health risks caused by indoor mycotoxins is not yet widespread in Germany. Reporting and monitoring programs for mycotoxins in water-damaged buildings seem to be necessary to provide insight into the occurrence of similar cases as the one described here.