Showering pigs with cold water during preslaughter lairage is thought to be useful in reducing the body temperature of hot, easily stressed animals. However, showering when the ambient temperature is too low could chill them too severely. To assess the effects of showering and to determine a temperature below which pigs should not be showered, pigs from one source, passing through a commercial slaughterhouse lairage, were split into two groups of approximately 50 each, showered and unshowered, on 10 days with a range of ambient temperatures. The pigs' behaviour and any damage to their skin were recorded, various measures of body temperature were taken before and after showering, and blood taken at slaughter was analysed for plasma creatine kinase, cortisol and lactate. Showering prevented the usual reduction in activity observed in pigs in lairage at high ambient temperatures. On the basis of the reduction in their flank temperature during showering, it is recommended that pigs should not be showered continuously if the temperature inside or outside the lairage falls below 5°C, and showering should cease if they are seen to be shivering.