Oedema disease usually occurs after weaning and is due to infection with Enterotoxaemic Escherichia coli strains. A total of 240 weaned piglets were used in five groups during a 28-day period. One group (a negative control) was offered feed free of antimicrobials ad libitum, three groups were offered the same diet ad libitum supplemented with either 1.6 per cent lactic acid, 1.5 per cent citric acid or 50 p.p.m. of enrotloxacin (ENR/Baytril I.E.R. 2 5 per cent, Bayer), respectively. Finally, one group was offered the same diet but the amount offered was restricted during the first 12 days post-weaning. Groups receiving acid or ENR additions to the diet had lower mortality than the negative control group (P<0.05). The three groups on treated feed also showed significantly better growth performance and food conversion ratio than the control group (P<0.05). Both organic acids and medication with 50 p.p.m. of ENR for a 10-day period are useful in controlling and/or preventing post-weaning oedema disease.