The prosecution's expert said Andrea Constand could have felt weak and woozy, with blurred vision and a dry mouth, as quickly as 10 to 15 minutes after taking pills that Bill Cosby gave her.
But a different expert called by Cosby's defense team said she couldn't have felt those symptoms so quickly or severely from the Benadryl that Cosby said he gave her.
The conflicting testimony Thursday came from two toxicologists, one called by each side in Cosby's sex assault retrial. It will be left to the jurors — who could get the case early next week — to determine which expert to believe, if either.
The full day of expert testimony came after jurors heard from six women, including Constand, who said Cosby drugged them before sexually assaulting them. The jury has also heard Cosby's own statements admitting that decades ago he obtained Quaaludes to give to women before sex.
But what drug he gave Constand on the night of the alleged assault in 2004 and how it impacted her is a central question at his trial.
Timothy Rohrig, a forensic toxicologist who testified for the prosecution, was the final witness called by prosecutors in their bid to prove that Cosby drugged and sexually assaulted Constand in 2004.
"All the symptoms she described, the timing of the onset of the symptoms she described, is consistent with the ingestion" of Benadryl, said Rohrig, who also testified at Cosby's first trial last June.
Alcohol, Rohrig said, would intensify the effects of Benadryl.
Harry Milman, the toxicologist called by Cosby's lawyers, testified that Benadryl is one of the safest over-the-counter allergy medications and would not have produced those severe effects.
"If it caused unconsciousness or an inability to move your arms or legs, then it wouldn't be an over-the-counter drug," Milman said. "And the symptoms that she described are very severe symptoms, and they all appeared at once."
Milman said that because Constand said she took only some sips of wine on the night of the alleged assault, it could not have caused her symptoms.
Cosby sat quietly, appearing to focus on the technical testimony as lawyers on each side tried to discredit the other's expert.
Assistant District Attorney M. Stewart Ryan suggested that Milman had no experience in drug-facilitated sexual assault cases, and was not board-certified.
"And you don't hold any sort of license?" Ryan asked him.
"I hold a driver's license," Milman responded, drawing laughter from the courtroom.
Cosby lawyer Kathleen Bliss, meanwhile, suggested that Rohrig's testimony about Benadryl and Constand's symptoms might be incorrect because the drug cannot cause paralysis or inability to speak.
Cosby told police and testified in a deposition for the civil lawsuit Constand filed against him that he gave her 1½ Benadryl pills that night.
Prosecutors insist that Cosby may have given her something other than Benadryl, because he previously refused to disclose the medication to Constand and her mother. Jurors also heard Cosby's deposition testimony that he had obtained Quaaludes to give to women he wanted to seduce, as well as testimony from five other women who said Cosby drugged and sexually assaulted them in the 1980s.
The experts also testified about Quaaludes, and their testimony on the effects of that drug differed as well. Rohrig said they made people act intoxicated while Milman said they could not make someone black out immediately, as some of Cosby's accusers described from the witness stand last week. All five of the other women who testified said they took pills or drinks given to them by Cosby. Only one, Janice Baker-Kinney, said she took Quaaludes.
Also Thursday, Cosby's lawyers sought Judge Steven T. O'Neill's permission to read decade-old testimony into the record from Sheri Williams, one of Constand's closest friends from her time in Philadelphia, whom they had hoped to call as a witness in their case.
Williams' name came up frequently during Cosby's first trial as prosecutors combed through months of Constand's phone records from the time of her alleged assault, showing frequent contact between the women.
Cosby's legal team has barely mentioned Williams in the retrial. However, in a court filing late Thursday, they said they had been unable to serve her with a subpoena and asked the judge to permit them to read portions of her deposition from Constand's 2005 civil suit against Cosby into the record instead. O'Neill said he would hear arguments about the issue Friday morning.
Defense lawyers are expected to call three witnesses to testify Friday, and at least one more on Monday. O'Neill told jurors that they could begin deliberating early next week.