ESSENDON players and the Australian Sports Anti-Doping Authority have each called medical specialists to give evidence at the AFL Anti-Doping Tribunal on Wednesday.
After six days of opening submissions from ASADA, current and former Essendon players launched their defence on Tuesday, with David Grace QC continuing to present their case on day eight of the hearing.
ASADA's lawyer, Malcolm Holmes QC, also called a medical specialist to give evidence in relation to the substances that are the subject of infraction notices.
The hearing, which is being held behind closed doors at the Victorian County Court, has also heard opening submissions from Neil Clelland QC on behalf of two former Essendon players, who are being represented separately.
The Tribunal will hear further submissions on Thursday on the admissibility of certain evidence to be considered by the Tribunal.
ASADA finished its opening submissions last Wednesday, alleging the 34 players and one support person, no longer employed by Essendon, breached the AFL Anti-Doping Code through the use of the banned peptide thymosin beta-4.
In December, ASADA lost a legal battle to have two of its key witnesses, biochemist Shane Charter and compound pharmacist Nima Alavi, testify at the hearing.
Charter and Alavi have given evidence to ASADA but refused to sign sworn affidavits backing the authority's allegations that the players were administered the banned drug thymosin beta-4 as part of Essendon's 2012 supplements program.
Lawyers for the players are arguing the players were given a legal version of thymosin - thymosin alpha-1 or thymomodulin.
The hearing is being held in private after a ruling by Tribunal chairman David Jones on December 8 last year.