Inhalation of organic particles (bacteria, fungi or animal proteins) by sensitized subjects is known to induce extrinsic allergic alveolitis (EAA). The most frequent type of EAA and the best known in rural environment is farmer's lung disease. Nevertheless a rarer form is also to be considered in rural environment: cheesewasher's disease. Here we report 4 cases of cheesewasher's disease, who all presented with relevant aspects of the disease: diversity of antigens involved, prophylaxis problems, severity of the disease, rapidity of onset, reversibility and importance of history in the diagnosis. Penicillium casei usually is the responsible antigen, and precipitating antibodies against these moulds, but against other moulds such as Aspergillus, Circinomucor circilloïdes, Fusarium as well, can be detected in the patient's serum. Thus, in a rural environment, a respiratory symptomatology suggestive of EAA should lead to thorough search for antigens and cheesewasher's disease should be considered. Among the many other diagnostic tests, precipitin determinations are cheap and non invasive and can be very useful in the diagnostic approach.