"Environmental medicine" is a new sub-discipline in the spectrum of medical specialization in Germany. The Berlin Academy of Occupational Medicine and Health Protection, now a branch of the Berlin Chamber of Physicians, developed a 200-lesson curriculum for physicians who want to specialize in this field. Coincidentally during the initial courses, the attendants were already highly qualified ("Facharzt"-level) and experts in various occupational fields, and hence the composition of the classes was highly heterogeneous on the levels of practical experience as well as theoretical knowledge. The Academy therefore decided to change the teaching method to Problem-Oriented Learning (POL). This required training tutors for small learning groups, supervision for these tutors and supplying adequate teaching materials and a stimulating environment for the student. The "Arbeitsgruppe Reformstudiengang Medizin" (Medicine Curriculum Reform Project) at the Berlin Humboldt University as well as the Dutch Rijksuniversiteit Limburg in Maastricht helped in the process of conceptualization. Participants worked in groups of up to 8 persons under non-directive tutors. A new "case" was presented every day, and the students developed individual learning goals according to the Seven Steps-method, which were then researched individually and with the help of outside experts. The findings were reported back and discussed in the group. Initially there was irritation, but after two or three days participants got used to not being lectured. Instead of being passive recipients of expert knowledge they felt that the POL method of learning enhanced their competence to act independently.