It all started with an $1,800 toilet-seat cover.

In that 1980s defense-spending scandal, U.S. Sen. Charles Grassley found a congressional calling: creating uproars that often transform public opinion and policy.

In his nearly 30 years in the Senate, the Iowa Republican has gone after the FBI, the IRS and others. But in recent years, Grassley has repeatedly turned his sights on wrongdoing by the pharmaceutical industry and its overseer, the U.S. Food and Drug Administration.

"The pharmaceutical industry feels it's got a seat at the table, whereas the only person that should have a seat at the table across from the FDA is John Q. Public," he said in an interview in his Senate office.

Hearings he held on Merck & Co. Inc.'s Vioxx and its heart problems helped get the drug pulled from the market. Grassley's revelations about prominent psychiatrists who failed to disclose large payments from drug companies have fueled investigations into conflicts of interest.

In late 2007, his staff's research revealed how GlaxoSmithKline P.L.C. allegedly bullied a scientist who identified heart problems associated with its diabetes drug Avandia. A follow-up report may be in the works. The London company, which has major operations in the Philadelphia area, has continued to say Avandia's benefits outweigh its risks.

But anyone expecting a firebrand will find that the stereotype of the stubborn, "aw shucks" Iowa farmer fits 75-year-old Grassley better.

His crusading seems populist, but his opposition to abortion and gun control has won him high marks from conservative groups. He is a teetotal Baptist with a sly sense of humor.

When Hustler publisher Larry Flynt sent free subscriptions of his magazine to members of Congress, Grassley skipped the moralizing speeches his colleagues gave in response and sent a letter:

"Dear Larry: Since you have sent me a slice of your mind, I'd like to send you a slice of mine. You will shortly receive your first installment of an annual subscription to Christianity Today."

His is a prairie populism wrapped in a big red, conservative, anti-government-waste, First Amendment bow.

He refuses to buy lunch at weekly meetings of Senate Republicans because they cost $25. He eats an apple and yogurt instead.

He developed a reputation for protecting whistle-blowers after he gave critics of Reagan-era defense spending a platform. They have come to him ever since, he said.

"Most whistle-blowers are just going about trying to make sure things are done right, that money is being spent correctly, and they don't get anyplace, so out of frustration, they end up coming to a congressman or a senator."

In 2004, FDA safety official Andrew Mosholder concluded that some antidepressants increased suicidal thoughts in children and teenagers. But his bosses forbid him from presenting his findings. At the time, the FDA said it simply wanted to speak with one voice.

Grassley found out and investigated. Later research proved Mosholder right, and today labels on those drugs warn about suicide.

"At the FDA, the scientific process is shortchanged a lot," Grassley said. The FDA has said it has been changing its culture, and, at a recent hearing on asthma drugs, an FDA scientist with a minority view within the agency was allowed to speak.

Grassley's doggedness has won praise.

"His scrutiny of the relationships between academic physicians and industry has resulted in greater transparency and accountability for our profession," said Steve Nissen, an Avandia critic and head of cardiology at the Cleveland Clinic, which recently started disclosing payments from drug companies to its researchers.

But some experts warn that Grassley has oversimplified challenging science. All drugs have side effects, and sorting out which are more dangerous is rarely simple, said John Calfee, a resident scholar who studies the drug industry for the conservative American Enterprise Institute.

"If anything, the FDA probably puts at least a bit too much emphasis on drug safety in comparison to getting faster drug development," Calfee said.

Grassley says he is simply providing a forum for competing scientific ideas, not deciding which ones prevail. Legislation he has proposed has been aimed at bringing more information into the open, he said, including restructuring the FDA to make it easier for agency scientists to speak out if safety problems come to light after a drug is on the market. He also wants drug and medical-device companies to publish payments to researchers and doctors on a public Web site.

Already, some institutions - including GlaxoSmithKline, Eli Lilly & Co., and the University of Pennsylvania - have pledged to disclose such financial relationships.

Jerome Kassirer, a professor at Tufts University School of Medicine and an expert on conflicts of interest, applauds Grassley's efforts, but wants changes that would abolish speaking fees, trips, and other payments to doctors that help drug companies promote their point of view.

"Transparency is only a partial solution to conflict of interest," Kassirer said.

Grassley has told him he's just getting started.