At UFC 200 in 2017 Mark Hunt lost to Brock Lesnar by unanimous decision. However, that decision was later overturned and changed to a no contest after it was revealed that Lesnar had tested positive for the banned substance clomiphene during a pre-fight drug test. Lesnar also tested positive for that same substance after the contest.
In response to this information Hunt sued the UFC, Dana White and Brock Lesnar. In his lawsuit he claimed that the UFC knew about Lesnar’s use of a banned substance before their fight.
A key detail in his lawsuit was that Hunt said he never consented to fight an opponent who was using banned substances and that losing to Lesnar had caused harm to his reputation and future earning potential.