Isabell Werth (born 21 July 1969 in Rheinberg) is a German equestrian and world champion in dressage who competed in the Olympics five times (1992, 1996, 2000, 2008, 2016) winning ten medals, six of them gold. She holds the record for the most Olympic medals won by any equestrian athlete.
Werth has competed in the Olympics five times in 1992, 1996, 2000, 2008 and 2016. In those five games, she won ten medals, six of them gold. Werth has also won seven Dressage World Championship medals, six of them gold. She has competed multiple times at the European Dressage Championships, earning several gold, silver and bronze medals. At the 2008 Olympics, she won the team championship together with her colleagues Heike Kemmer and Nadine Capellmann. At the 2016 Olympics, Isabell won the team championship once again, this time with Kristina Bröring-Sprehe, Dorothee Schneider and Sönke Rothenberger. A few days later she added an individual silver medal, her 4th individual Olympic silver.
Werth rode Gigolo, owned by Uwe Schulten-Baumer, her coach from 1986 until 2001. On Gigolo, she won all her championships between 1992 and 2000, save for the 1999 European Championships in Arnheim, where she rode Anthony FRH. In 2006, she started riding Warum Nicht FRH at the international level and with him won the 2007 World Cup in Las Vegas. Warum Nicht retired in 2012. Werth competed at the Olympic Games with Satchmo, who subsequently retired in November 2011. In 2010, Werth started riding El Santo at the international level until the horse was transferred in 2016 to Spanish rider Jose Antonio Garcia Mena. In 2016, Werth secured the ride on Weihegold Old, with whom she won the team gold medal and a silver medal in the Individual Dressage at the Rio Olympics.
Isabell Werth worked alongside Bates Australia to develop the Isebell Dressage Saddle available in Bates and Wintec.
On 24 June 2009, the forbidden substance, fluphenazine was found in the A-sample from Werth's horse Whisper at a Whitsun tournament at Wiesbaden. She was suspended from all tournaments by the International Federation for Equestrian Sports. On 2 September 2009, the suspension was set by the FEI to six months from 23 June.
Werth subsequently stated that the drug was given to the horse to treat equine shivers—mainly for the safety of the horse's handlers—and that she does not believe the drug influences a horse's ability to compete.