Interstate Horseracing Improvement Act of 2011

Interstate Horseracing Improvement Act of 2011 - Amends the Interstate Horseracing Act of 1978 to prohibit: (1) entering a horse in a race that is subject to an interstate off-track wager if the person knows the horse is under the influence of a performance-enhancing drug; or (2) knowingly providing a horse with such a drug if the horse, while under the influence of such drug, will participate in a race that is subject to an interstate off-track wager.

Prohibits a host racing association from conducting a race that is the subject of an interstate off-track wager unless it has in place a policy that: (1) bans providing a performance-enhancing drug to a horse that will participate in such race while under the influence of the drug, (2) bans the racing of a horse that is under the influence, and (3) requires that an accredited third party conformity assessment body test the first-place horse and one additional randomly selected horse for any such drug and report any test results demonstrating that a horse may have participated while under the influence to the Federal Trade Commission (FTC) and any host racing commission that entered into an agreement to enforce this Act's provisions.

Sets forth penalties for violations, including: (1) civil penalties and suspension of a person providing a horse with such drug, and (2) suspension of a horse that is provided with such a drug or that is raced in violation of this Act. Provides for enforcement of this Act through private civil actions and by the FTC, including through an agreement with a host state's racing commission.