Salicylic acid is a substance found in the normal feed of horses such as lucern and hay. During previous years large populations of racehorses from all over the world were screened for natural levels of salicylic acid which is ingested in such feeds. Considering the possible diets of horses and worst case scenarios, a single salicylic prosecution threshold was decided on an international basis. This International Federation of Horseracing Authorities (IFHA) threshold has been established with an extremely high probability that untreated horses on a variety of feeds will present levels far below this salicylic acid threshold. 

The NHA has formally adopted this threshold:  “Salicylic acid…… 6.5 micrograms salicylic acid per millilitre in plasma” as shown on the website. A specimens is only declared a positive finding when the concentration of salicylic acid is accurately confirmed (full quantitative analysis is conducted as part of such a positive finding) to exceed this threshold, in accordance to Rule 73.4.4.  
It is know that Aspirin can be added to the feed of horses to acts as an analgesic and anti-inflammatory substance. Acetyl salicylic acid (Aspirin) is however a pro-drug of salicylic acid, implying that Aspirin will be converted to salicylic acid within the horse.  As Aspirin it is not a scheduled substance (in contrast to most analgesic and anti-inflammatory substances) it can be readily obtained by all. The administration of Aspirin to the racehorse must be recorded in the Veterinary Treatment Register of the horse. The use of Aspirin too close to race day is likely to result in salicylic acid prosecution. Be aware that guidance of the use of Aspirin products in the horse differ between different manufacturers.

Following the administration of a single dose of Aspirin a detection period of a two days applies (this is not a withdrawal time). Consult your veterinarian in regards to a suitable withdrawal period. The NHA does not assume any legal, professional or other responsibility or duty whatsoever as to the accuracy of the data presented in this document. Please note that reliance on and use of the above information does not absolve or diminish a trainer or owner from being responsible for ensuring that the horse complies with the rules relating to the presence of drugs and prohibited substances when presenting a horse for a race.


Adrenocorticotropic hormone, commonly called ACTH, is a protein hormone naturally produced in the horse. The function of ACTH is to stimulate and also regulate levels of the steroid hormone cortisol. Commercially available ACTH is a synthetically produced peptide hormone which is high similar in structure to ACTH produced naturally. As a prohibited substance in horseracing the use of synthetic ACTH is most commonly monitored and prosecuted by the increase which is observed the level of naturally produced hydrocortisone. As the hydrocortisone level increases beyond the international threshold, this is prosecuted as a prohibited substance offence. 

There are also other approaches to detect the use of synthetic ACTH. One of these is based on the fact that synthetic ACTH corresponds to the structure of human ACTH. It can therefore be detected in the horse as the structure of this protein is somewhat different to naturally produced ACTH in the horse.  The NHA Laboratory is one of a few racing laboratories which have been active in the research of new approaches for the detection for synthetic administered ACTH in the race horse. During recent years ACTH administration trials were conducted on horses as part of such research at our Laboratory.  This research was formally presented at an international conference for horse racing chemists and veterinarians.

It must be noted that at least one web based sales company is selling a product which purport to contain the biochemically active molecule of ACTH. Several racing laboratories have already analysed this preparation. Such analysis however indicated that the active peptide ACTH is either not contained or is only contained in a very low concentration, certainly too low to effect the horse.


Erythropoietin (EPO) is natural occurring protein hormone which has the function to increase red blood cell production in the horse. Natural EPO can be supplemented by the administration of several different forms of human EPO to the horse. At the NHA Laboratory the screening of  human EPO in horse specimens is being undertaken employing a sophisticated immuno-detection screening methodology which is widely reported as the most accurate and sensitive currently available to the racing industry.  A highly attractive aspect about this is the wide range of EPO types which are covered, as was been confirmed by EPO administration and research studies at racing laboratories.  Included in the effective coverage of the screen is conventional EPO forms such as Epogen, Eprex, Epoetin-alpha, Epoetin-beta and Procrit and even longer acting EPO types called darbepoetin alfa (Aranesp, DPO) and CERA (PEG Epoetin-beta, MirCERA).

Growth Hormone (GH) refers to a natural hormone within the horse which is anabolic and which has the effect to enhance cell growth and cell recovery. In addition to this natural occurring equine GH there are a range of synthetic GH’s from several animal species which are active in the horse. These include a modified form of equine GH, bovine (cattle) GH and porcine (pig) GH. The NHA Laboratory employs a sensitive immune-detection screening approach which was shown effective in detecting the use these hormones by means of the measurement of the amount of the messenger protein “IGF-1”. The screening methodology measures the IGF-1 concentration against the level which is normal in the horse and can also detect the use of and some IGF-1 analogues and synthetic IGF-1 forms. The NHA Laboratory was a few years ago, in partnership with a few other countries, instrumental in conducting important research into suitable screening methodologies and validating these screening approaches.

The NHA recognises the threat which these Class 1, Forbidden Substances pose to the integrity of racing and the welfare of the horse and for this reason these screening methods have been in place at the NHA for many years.


Non-steroidal anti-inflammatory drugs (NSAID’s) are pharmaceutical substances which are prescribed for the treatment of muscle and joint injury, pain, swelling and inflammation. In the form of tablets, capsules and injections these can also be obtained by medical prescription or as dispensed by a pharmacist. These non-steroidal anti-inflammatory drugs contain however also be obtained in certain products which do not have a pharmaceutical schedule which are sold in shops without a prescription. The purchase and use of such preparations in racehorses can results in positive findings for these prohibited substances. These preparation are normally gel and plaster packs with trade names such as:

  • Voltaren Emulgel containing Diclofenac
  • Fastum containing Ketoprofen
  • Transact containing Flurbiprofen 

It is important that care is taken when purchasing such substances and when using such preparations on horses. Consult with your veterinarian in this regard.