Halfway through his nearly 5-hour stint in the grand jury room, Barry Bonds popped his head into the hallway and asked: "Is my mother here?"

In fact, she was. But she left long before Bonds finished his testimony to grand jurors focusing on possible tax and drug violations by a California lab that supplied nutritional supplements to Bonds and other sports stars.

Bonds, wearing a sports jacket and tie, became the highest-profile athlete to appear before the grand jury.

The six-time National League (search) MVP entered the grand jury room late Thursday morning accompanied by attorney Mike Rains and left in the late afternoon — though it was unclear how long he testified.

"It went fine," Bonds said as he was led by two bodyguards and two federal marshals to a freight elevator that was held for him. He was taken directly to the garage of the federal courthouse, then driven away as a marshal stopped traffic.

Bonds' wife and mother sat in a nearby hallway during most of his appearance.

Benito Santiago, a free-agent catcher who spent the past three seasons as Bonds' teammate with the San Francisco Giants (search), testified for 45 minutes later in the afternoon.

His attorney, David Cornwell, fears athletes who appear before the grand jury will be unfairly ostracized.

"My only concern is that there seems to be almost an undercurrent that stigmatizes these guys, which I think is inappropriate," Cornwell said.

Bonds has attributed his muscular development over the years to intense weight training, proper diet and a regimen of nutritional supplements from companies such as the Bay Area Laboratory Co-Operative (search), or BALCO, that is at the heart of the grand jury probe.

Bonds repeatedly has denied using steroids.

Thursday's appearance gave grand jurors the chance to ask the Giants slugger under oath whether his growth has been entirely natural.

Other athletes that already have appeared before the grand jury include track star Marion Jones and her boyfriend, 100-meter world record-holder Tim Montgomery, four Oakland Raiders players and Olympic champion swimmer Amy Van Dyken.

An appearance before the grand jury, or being subpoenaed to testify, does not mean an athlete is a target of the probe.

Two people have been named so far as targets of the grand jury — BALCO founder Victor Conte, and Greg Anderson, Bonds' personal trainer.

Bonds, 39, became a BALCO client just before his record-setting 2001 season, in which he hit 73 homers, and has praised Conte for giving him a personalized nutritional program.

Anderson's home was raided by the Internal Revenue Service and a drug task force Sept. 5, two days after a similar raid at BALCO.

Bonds brought Anderson, a childhood friend, on a major league tour of Japan after the 2002 season, when the trainer met players such as Jason Giambi — who also has been subpoenaed to testify before the grand jury.