John M. Ashbrook, an articulate Harvard-educated Republican congressman from Ohio, who championed conservative principles with a vigor and independence of spirit that led him to run against President Nixon for the GOP nomination in 1972, died yesterday of internal bleeding. He was 53.

Rep. Ashbrook, a congressman for 21 years, was a candidate for the Republican nomination to oppose Sen. Howard Metzenbaum (D-Ohio) in this November's Senate election.

The 11-term representative, who was a lawyer, newspaper owner and the son of a former Democratic congressman, collapsed in Johnstown, Ohio, where he had a home and office. He was taken at 12:06 p.m. to Licking Memorial Hospital in Newark, Ohio, where he was pronounced dead 22 minutes later.

Preliminary autopsy results showed he died of "a massive gastrointestinal bleed" that stemmed from inflammation of the lining of the stomach and small intestine.

Rep. Ashbrook, a founder and former chairman and director of the American Conservative Union, had collapsed March 17 in a restaurant in Mansfield, Ohio, and was examined by doctors there and in Cleveland. Aides said afterward that he was suffering from exhaustion brought on by the rigors of campaigning for the June 8 primary.

Describing himself as "shocked and grieved" by Rep. Ashbrook's death, Sen. Metzenbaum expressed his sympathy to the congressman's family.

The ranking Republican on the House Education and Labor Committee and a Reagan administration supporter in last year's budget battles, Rep. Ashbrook was praised by President Reagan in a statement yesterday as a man of courage and principle who "served his constituents and his country with dedication and devotion, always working toward the betterment of his fellow man.

"His patriotism and deep belief in the greatness of America never wavered and his articulate and passionate calls for a return to old-fashioned American values earned him the respect of all who knew him," the president said.

The decision made by Rep. Ashbrook in 1971, months before the Watergate break-in, to run against Nixon in the 1972 primaries, appeared to be the capstone of years of resolutely outspoken advocacy of conservative principles, often, as in the presidential challenge, with small hope of carrying the day.

Impatient with those conservatives who he said deferred to "bosses in a smoke-filled room" rather than to conscience, Rep. Ashbrook, owner of the Johnstown Independent and three other weekly newspapers, once said his greatest political asset "is that I'd rather be a printer.

"So," he added, "I don't have to worry that much about a political future and I don't have to trim."

His challenge to Nixon, he said, was intended not to wrest away the nomination, but instead to focus what he called conservative dissatisfaction with the Nixon administration's "leftward drift."

He denounced budget deficits, wage and price controls and rapprochement with China.

Although many prominent conservatives, including Sen. Barry Goldwater, opposed Rep. Ashbrook's candidacy, they did not deter him.

"I still believe it is in the best American tradition to speak out, even when it is in criticism of your party's actions," he said. "I have not and will not shirk from that role, regardless of the consequences."

After failing to get more than 10 percent of the vote in four early primaries while watching campaign contributions dwindle, Rep. Ashbrook, who had been a founder of the draft-Goldwater organization in 1963 and had supported Nixon at the 1968 convention, finally dropped from the 1972 race.

Known as one of the most ardent congressional advocates of states' rights, and of what he said was protection of individual freedom against government interference, Rep. Ashbrook criticized what he called "Gestapo-type" actions against gun collectors and dealers by the federal Bureau of Alcohol, Tobacco and Firearms. He moved to curb the power of the Internal Revenue Service to determine whether private schools discriminated by race and should thus lose their tax exemptions.

He said in 1979 he wanted to return IRS to its role as a collection agency rather than an "instrument of social engineering."

He also sponsored a measure to forbid use of federal employes' health insurance to pay for most abortions.

Rep. Ashbrook was a son of the second marriage of William A. Ashbrook, who served in Congress from 1907 to 1921. The elder Ashbrook was elected again in 1934, when he was 67 years old and his son was 6.

After high school in Johnstown, Rep. Ashbrook served in the Navy as a storekeeper first class on Adm. Richard E. Byrd's final Antarctic expedition in 1946-47. He then enrolled at Harvard, where, he said, he "started out as a conservative, but my professors and what they taught me made me even more so."

Subsequently, he took a law degree from Ohio State University, entered local Republican politics and became chairman of the Young Republican National Federation. After two terms in the Ohio legislature, he defeated a Democratic incumbent to win his first race for Congress in 1960, on a platform of individual freedom.

His 1948 marriage to the former Joan Needles ended in divorce in 1971. He later married the former Jean Spencer. He was the father of three daughters, Barbara, Laura and Madeline. Also surviving are his mother Marie, sisters Lea and Lucy, and his brother William.