NOW BOB Strauss knows how Hamilton Jordan feels.

Celebrity publicist Barry Landau, one of the witnesses against Jordan regarding the "Studio 54" cocaine allegations which a special prosecutor found to be without substantiation, is the source of an item which appeared recently in at least one gossip column about Strauss and actor Walter Matthau.

The story isn't true, Strauss says, but Matthau is so pleased about it that he carries a clipping around in his wallet to show anyone who's interested.

The clipping claims that Strauss recently lost $12,000 to Matthau in a poker game at La Costa in California.

Matthau told Strauss that the item has improved his luck because opponents are even more uncertain now when he is bluffing.

Landau, after a recent trip to La Costa, had been telling the Matthau-Strauss story to columnists along with a second item he would like to see brought to the attention of his friends and enemies. He's busily writing his memoirs, a disclosure more tantalizing, if true, than the Strauss-Matthau tidbit, because Landau knows enough secrets about celebrities to write one of the most sensational books of the decade if he were so inclined.

It will come as no surprise to the media if Bill Gulley, former head of the Military Affairs office at the White House, is contacted by the special prosecutor in the Tim Kraft investigation, the latest drug-related investigation to plague this administration.

Gulley, who has been out around the country promoting his new book, "Breaking Cover," has been telling interviewers that he became concerned about alleged drug usage by top Carter aides at the very beginning of this administration.

He was so concerned, he says, that he notified the White House infirmary to be on the alert for the medical and legal ramifications.

Gulley could find himself subpoenaed to tell a grand jury whether he has first-hand knowledge or just hearsay.

Because she "already has so many diamonds," Eva Gabor got two cats for one wedding anniversary and more orchids another year to add to the 1,000 plants she already has blooming in a special hot-house in her Holmsby Hills mansion.

This September, when the date rolled around again, her practical husband, industrialist Frank Jameson, had a rug she wanted custom-woven in Hong Kong.

He's running out of ideas. "She's a woman who expected presents almost every day," he says. "Even on Hungarian National Defense Day."

Former New York Timesman, Tad Szulc, a biographer of convicted Watergate burglar E. Howard Hunt and an expert on the international world of espionage and intrigue, is telling friends that he is forsaking fact for fiction. Szulc has finished a new novel, already sold to the movies, which reportedly could make him the new Ian Fleming.

Friends of former attorney general John Mitchell say he has bought into an Italian restaurant here. But Mitchell, still bitter with the press, will never comment one way or the other on what he's up to.