From The Stargate Omnipedia

Medical doctor stationed at the Alpha Site on P4X-650. When the Tok'ra were suspected of using symbiote poison on Goa'uld-controlled planets, the doctor verified that Jaffa found dead on P4S-161 were indeed killed by the material -- which the Tok'ra had developed.


Endgame - Colonel Pierce informs Teal'c that Dr. Harris examined several Jaffa bodies on P4X-650 and insured him that symbiote poison was responsible for their deaths.