When cholera broke out in Mozambique, Kenya, Tanzania and Uganda in 1997, an urgent measure was filed with the Sanitary and Phytosanitary Committee of the World Trade Organization, by the European Union, citing the protection of human health, to limit imports of fish products. The authors analysed import data on specified products over time to quantify the trade impact of this measure. Using previous specific trade trends, the authors modelled expected trade flows and compared observed imports with expected imports to calculate the potential cost of lost trade. The conclusion of this analysis was that the impact of European restrictions on fish exports from Mozambique, Kenya, Tanzania and Uganda on the economies of these African countries was at least US dollar 332,217,415 for the years 1998 to 2002. Insights from such quantitative studies will be important in making policy choices under the revised International Health Regulations of the World Health Organization and should inform the discussion about the adoption of these regulations.