In 1854 a Cholera Epidemic struck London. This was the first time the
medical community was able to trace the outbreak of an epidemic to one particular source (in this case a public
water pump). By the end of it around 500 people had died.
The House of Commons asked for a report about the various methods that had been used in
treating the epidemic. When the report was issued, the homeopathic
figures were not included. The House of Lords asked for an explanation,
and it was admitted that if the homeopathic figures were to be included
in the report, it would “skew the results.” The suppressed report
revealed that under allopathic care the mortality was 59.2% while under
homeopathic care the mortality was only 9%!
here’s the wikipedia entry (characteristically omitting to mention homeopathy’s involvement!)