“Who does that?” she said. “A person that puts profit over everything else?”

When Judge Matsumoto told prospective jurors that Mr. Shkreli’s work in pharmaceuticals was not on trial, the prosecutor Alixandra Smith objected.

“If the defendant takes the stand and testifies,” she said, prosecutors may introduce some of his exploits in the pharmaceutical world, too.

Other potential jurors had bad reactions to Mr. Shkreli himself.

One said she had not known what the trial was about when she walked in and saw Mr. Shkreli. “I looked right at him, and in my head, I said, ‘That’s a snake’ — not knowing who he was,” the woman said.

After the potential juror had stepped down, Benjamin Brafman, a lawyer for Mr. Shkreli, said, “So much for the presumption of innocence.”

The potential jurors were questioned at a sidebar with Judge Matsumoto, defense lawyers, prosecutors and one reporter from a news pool.

The negative comments built up to the point that Mr. Brafman began to signal to Judge Matsumoto when potential jurors had said enough that he could challenge them for cause, to stop them from going “on a tirade against Mr. Shkreli.”

Mr. Brafman said that he and the rest of Mr. Shkreli’s legal team had objected to the reporter’s presence at the sidebar for that reason, among others.