An inquiry into the Alligator Blood positive swab from the Magic Millions 3YO Guineas has been set down for July 23.

Sunshine Coast trainer David Vandyke will face Racing Queensland stewards after the sample was confirmed to contain the prohibited substance altrenogest.

Altrenogest, more commonly known as Regu-mate, is banned for use on male horses.

It is a hormone given to keep female horses from being in season, or if they are already pregnant, to keep them from losing the foal.

Vandyke was informed in March of the irregularity but a final inquiry date was not set until Thursday.

The inquiry will be held against a backdrop of threatened legal action by Alligator Blood's major owner Allan Endresz.

Stewards are also understood to have taken external legal advice.

Connections face losing the $1.2 million first place prize money if Alligator Blood is disqualified.

Alligator Blood won two races after the Magic Millions including the Group One Australian Guineas.

He is in line for a place in the $15 million Everest in October.