Several European countries, including Norway, Sweden, and the United Kingdom, experienced a sudden increase in the number of Shigella sonnei infections. Epidemiologic evidence implicated iceberg lettuce imported from Spain. A number of the case-patients had double infections with other enteropathogens. In one county in Norway, in June, at least 45 outbreaks of gastroenteritis occurred in which iceberg lettuce was a common vehicle. Shigella was not isolated from the lettuce, but Salmonella and high fecal coliforms were identified. The imported iceberg lettuce harbored Escherichia coli strains showing resistance to several antibiotics. The outbreak subsided when imported iceberg lettuce was no longer available in the market.