The adverse health effects of indoor mold exposure gained much public attention in recent years. Although many studies support the involvement of fungi in building-related illnesses and emphasize the importance of mold exposure as an emerging public health issue, the role of toxigenic species such as Stachybotrys chartarum (SC) remains highly controversial [1]. Widespread litigation is making it more contentious, and the existing scientific information does not offer sufficient evidence that could lead to a better understanding of the problem and development of comprehensive public health policies. The article by Nagayoshi et al. [2] published in this issue of Mycopathologia describing for the first time the remodeling of pulmonary arteries in mice as a result of inhalation exposure to the spores of S. chartarum significantly extends our knowledge of the pathologic effects of this fungus. The ability to produce potent trichothecene mycotoxins became a source of great concern about S. chartarum. Approximately one-third of the isolates from the United States and Europe represent a chemotype that synthesizes macrocyclic trichothecenes [3]. Macrocyclic trichothecenes are not found in SC isolates belonging to the second chemotype which produces atranones. However, both chemotypes can synthesize much less potent simple trichothecenes. Molds can affect human health through mycotoxicosis, infection, allergy, and inflammation. The first category is often disputed, especially in the context of residential indoor air exposure [1, 4]. Arguments against the role of S. chartarum in building-related diseases are mostly based on the projection that the relatively low concentrations of the SC spores found in most indoor environments are insufficient to cause severe systemic toxicoses. Such opinions do not take into account local toxic effects at the site of deposition of fungal particles where the toxins can reach millimolar concentrations. Reports focusing on mycotoxins tend to present the ‘‘toxic black mold,’’ as S. chartarum is known to the public, as a species with unique properties compared with other fungi. While its high toxigenic potential clearly sets it apart, the effects of different fungal compounds common to all fungi such as b-D-glucan, proteins including hemolysin and proteases or various low-molecular-weight metabolites are likely to play a significant role in pathophysiology of this species [5–9]. In recent years, a number of animal studies of pulmonary effects of S. chartarum have been published, utilizing different animals/strains, different fungal isolates, and experimental protocols. The common finding was lung injury and inflammation. Some of those effects were paralleled in the experiments conducted with pure trichothecene toxins or atranones but toxin-independent mechanisms were also postulated [1, 10, 11]. It is I. Yike (&) D. Dearborn Department of Environmental Health Sciences, Case Western Reserve University, School of Medicine, Location Code 4940, Room WG19, 2109 Adelbert Rd., Cleveland, OH 44106, USA e-mail: ixy@case.edu