A San Francisco transplant surgeon accused of trying to hasten a man's death to harvest his organs pleaded not guilty Monday to felony administering a harmful substance knowing it would cause injury and possibly death.

Dr. Hootan Christopher Roozrokh, 33, entered the plea in San Luis Obispo County Superior Court, more than a month after entering not guilty pleas to two other felonies he's facing.

Rosa Navarro, the mother of victim Ruben Navarro, attended Monday's hearing and said she'll be at every hearing until justice is served.

“I'm here for my son,” Navarro said through tears. “(Dr. Roozrokh) did wrong, and I hope nobody has to go through (what my son did) again.”

She said justice will be served when Roozrokh is sent to prison.

Ruben Navarro, 25, of San Luis Obispo was dying of a rare metabolic disorder when he was sent in early February 2006 to Sierra Vista Regional Medical Center in San Luis Obispo.

Navarro weighed only 80 pounds and suffered from adrenal leukodystrophy, cerebral palsy, severe chronic neuromuscular and cognitive defects and a seizure disorder, when admitted to the hospital for cardiac arrest. He was also in a coma.

On Feb. 3, Navarro was transferred to the hospital's operating room, where he was taken off life support so that his organs could be harvested by Roozrokh and a transplant team.

It's alleged in the complaint against Roozrokh that he ordered lethal doses of the pain-killer morphine and sedative Ativan be given to Navarro in an effort to speed up his death.

In September, Roozrokh pleaded not guilty to one count of dependent-adult abuse and one count of administering unlawful controlled-substance prescriptions - morphine and Ativan - that weren't used for legitimate medical purposes. He was also accused of mixing those two substances with the topical antiseptic betadine.

The doctor didn't enter a plea to the single count of administering a harmful substance in September; instead his attorney M. Gerald Schwartzbach filed a demurrer, delaying the plea until Monday.

Schwartzbach argued Monday that the district attorney's filing of the charge didn't meet the statute because of the language used in the count.

Demurrers are typically filed in civil cases to argue that even if the facts presented in the case are true, they aren't legally sufficient for the case to proceed.

“What they alleged wasn't a crime,” Schwartzbach said outside the courtroom after the hearing. “They didn't use language that constituted a violation of the statute.”

Count 2 - the single count of administering a harmful substance - stated that the “harmful substance” was “introduced,” which didn't follow the statute that says the substance is “taken” or “ingested,” Schwartzbach said.

“Introducing (a substance) to someone is different than taking or consuming,” Schwartzbach argued. “Knowing that someone takes or ingests something is not what the people have alleged.”

After arguing the demurrer, prosecuting attorney Karen Grey submitted an amended complaint for Count 2 that changed the language, making it fit with the statute and nullifying the demurrer. Roozrokh then pleaded not guilty to the charge.

If convicted of all three counts, the surgeon faces potential punishments ranging from eight years in state prison to probation, with up to one year in jail and a $20,000 fine as conditions of probation, according to the District Attorney's Office.

A preliminary hearing date hasn't been set for the case.