The ambition to reduce direct and indirect damage of livestock by liver fluke disease by adequate control measures, provided the economic basis for the development of a system by which F. hepatica infection may be predicted. In doing simulation studies at various levels, efforts were made to provide a basis for this prognosis by the ecological and parasitological research programme of the Central Veterinary Institute. Besides the rate of growth, the survivorship curve of eggs and larval stages in various environments were studied as well. The relationship between F. hepatica infections and the establishment of liver fluke disease was studied by experimental infection in cattle and sheep. This strongly suggested that, in addition to the dose rate, the rhythm of (re-)infection is also an important factor in the expression of liver fluke disease. These experiments are designed to establish a sound basis for the strategic use of anthelmintics in the future. Moreover, they are essential to the evaluation and prediction of the epidemiology of liver fluke disease.