Olympic dressage rider Isabell Werth has been suspended from competition for 6 months after her horse El Santo NRW tested positive for a prohibited medication at the Rhineland Championships in Langenfeld last year (21-24 June 2012).

El Santo tested positive for cimetidine — a drug that is used to treat stomach ulcers. The drug is on the forbidden substances and prohibited medication in competition list for the German Equestrian Federation, but is not considered to be a doping substance.

Cimetidine is not banned by the FEI and is allowed in competition providing certain procedures are followed.

A statement released by the German Federation stated that officials believed that the horse was accidentally contaminated with the substance. But contamination is still considered a breach in duty of care in the organisation of stable management which means that, as the rider, Isabell is still responsible.

Isabell has argued that the contamination happened due to a failure in her stable watering system. The German Federation said it found this explanation “extremely unlikely”.

As a result of the findings, the disciplinary commission has banned Isabell from competing nationally and internationally for 6 months. She has also been fined €2,000 (£1,681).

Isabell still has the right to appeal the decision through the Court of Arbitration for Sport.

This is not the first time that Isabell has faced an international ban. In 2006 she was banned for 6 months when her small tour horse Whisper tested positive for banned substance Fluphenazine at a CDI Wiesbaden in Germany.