The relative radiation hazards from early and delayed fallout following a nuclear attack have been reviewed. It is indicated that the hazard to life from whole-body gamma irradiation from early fallout far outweighs the hazard from radioactive contamination of food. Nevertheless, because of the possible effects of iodine-131, the consumption by infants of fresh milk from animals which have ingested contaminated fodder should be avoided if possible during the first few weeks after attack. During the same period, water from covered supplies should be used in preference to that from open reservoirs. It is more important, however, to alleviate hunger and thirst in both man and animal than to prevent the temporary ingestion of food which may be contaminated by fallout.