The use of antibiotics in the livestock sector is increasing to such an extent that it can lead to negative aspects for human health, animal health and the environment. Homeopathy might be an alternative to antibiotics and has therefore been tested in a randomized placebo-controlled trail to prevent Escherichia coli diarrhoea in neonatal piglets. On a commercial pig farm 52 sows of different parities, in their last month of gestation, were treated twice a week with either the homeopathic agent Coli 30K or placebo. The 525 piglets that were born from these sows were scored for occurrence and duration of diarrhoea. Piglets from the homeopathic treated group had significant (P=0.0012 on pig-level and P<0.05 on sow-level) less E. coli diarrhoea than piglets in the placebo group. The occurrence of diarrhoea seemed to be less severe in the homeopathic treated litters, where the disease did not spread further and duration tended to be shorter. Especially piglets from first parity sows gave a good response to treatment with Coli 30K. Homeopathic treatments in the livestock sector, in this case to prevent diarrhoea, could be a solution to lower the current use of veterinary antibiotics.