Leo Sternbach, 97, who created Valium, the nation's most-prescribed drug during the 1970s, until critics claimed it was overused and newer drugs replaced it, died Sept. 28 at his home in Chapel Hill, N.C.

Sternbach became a celebrated figure in research science for his creation of a group of chemicals that soothed anxious, irritated and agitated executives and housewives. Valium topped the list of most-common pharmaceuticals from 1969 to 1982, with nearly 2.3 billion pills passing into consumers' hands during its peak sales year of 1978.

Nicknamed "Mother's Little Helper" and "Executive Excedrin," Valium was a true cultural phenomenon. The Rolling Stones sang: "She goes running for the shelter of a mother's little helper, and it helps her on her way, gets her through her busy day." Novelist Jacqueline Susann called the pills "dolls" in her 1966 novel "Valley of the Dolls." In a 1979 memoir, "I'm Dancing as Fast as I Can," television producer-author Barbara Gordon said quitting Valium cold turkey landed her in an insane asylum.

Horrified, a Senate health subcommittee held hearings on tranquilizer addiction in 1979.

Sternbach, who had tested the basic chemical compound on himself while developing it, said he didn't use Valium because it made him depressed. But neither did he consider its creation a curse, once saying that everything can be abused.

"Not enough people kept in mind the suicides that were averted and the marriages that were saved because of this drug," he told U.S. News & World Report in 1999.

Valium was a convenient substitute for alcohol, one researcher noted, because it didn't taste bad, it didn't smell and it was easy to carry. It is almost impossible to die from it, unless it's mixed with alcohol or other drugs. Used in small doses and for a limited period, it is an effective muscle relaxant, but many patients also say that its very success as a reducer of pain made it psychologically addictive.

Its popularity presaged such tricyclic antidepressants as Elavil and Nardil in the 1980s, followed by the class of drugs that includes Prozac, Zoloft and Paxil.

Celebrities almost tripped over themselves admitting to an addiction to it: Elizabeth Taylor confessed to a strict diet of Valium and Jack Daniel's; comedian Rodney Dangerfield daily swallowed it along with 136 other pills; and Ronald Reagan adviser Michael Deaver, in hot water for lying to a federal grand jury, attributed his perjury to a Valium-induced haze. Tammy Faye Bakker acknowledged a fondness for a Valium-and-nasal spray cocktail. Feminists attacked it as a symbol of physicians' insensitivity to women's medical complaints.

Sternbach's independent streak allowed him to make his discoveries. As a youth in his native Abbazia, then part of the Austro-Hungarian empire, he scavenged gunpowder from unexploded World War I shells and swiped chemicals from his father's pharmacy to make fireworks.

With a doctoral degree in organic chemistry from the University of Krakow, he went to work for Hoffmann-LaRoche in Switzerland and came to the United States in 1941, when all the company's Jewish scientists fled Europe at the beginning of World War II. At LaRoche's research facility in Nutley, N.J., he spent two years in the mid-1950s trying, without success, to duplicate Wallace Laboratories' new Miltown tranquilizer. His bosses urged him to forget tranquilizers and move on to antibiotics.

He disregarded the directive, and, tinkering with an abandoned experiment, he reworked the compound a bit and created chlordiazepoxide. It became known as Librium, a mild drug far less likely to cause sleepiness or addiction than anything then on the market as a tranquilizer.

He continued his research and by the end of 1959 came up with diazepam, which LaRoche's marketing department dubbed Valium, after the Latin word for healthy. Better than Librium because it was more effective in smaller doses, and useful for more problems, the drug prompted the company to launch one of the most intensive advertising campaigns in history, up to that point. Valium brought in $600 million in 1978 alone.

Sternbach was paid $1 for the patent to this pharmaceutical gold mine and $10,000 per year for 10 years.

His other major breakthroughs include the sleeping pills Dalmane and Mogadon, Klonopin for epileptic seizures and Arfonad for limiting bleeding during brain surgery. He held more than 240 patents.

In 2004, the Wall Street Journal said he developed 12 drugs that had a total of $10 billion worth of sales over four decades. For years, profits from his inventions accounted for 40 percent of LaRoche's annual drug sales.

He didn't care that his discoveries didn't make him a multimillionaire. "What's important is that you love the work you do," he said.

Named one of the 25 most influential Americans of the 20th century by U.S. News & World Report, Sternbach had a Yale University lecture named after him, and he was inducted into the National Inventors Hall of Fame in 2005.

A ramrod-straight man, bespectacled, with a shock of white hair, sparkling blue eyes and a piquant sense of humor, Sternbach occasionally would ski to his New Jersey office.

He and his wife moved to North Carolina in 2003.

His elder son said Sternbach became weak and bedridden about a week ago. He did not have a chronic disease.

"No medications, nothing," Michael Sternbach said. "His lungs were clear, his heart, kidneys and mind were functioning. He just went into a general decline and stopped breathing."

Survivors include his wife of 64 years, Herta Kreuzer Sternbach, of Chapel Hill; two sons; and five grandchildren.

Leo Sternbach, shown with his wife, Herta, in 2003, held more than 240 patents.