Johnson & Johnson's McNeil Consumer Health division has now announced it is recalling one lot (roughly 34,000 150-count bottles) of Tylenol 8 Hour Extended Release Caplets.
"McNeil is taking this action as part of our ongoing surveillance and monitoring efforts that identified a small number of complaints of a musty or moldy odor," McNeil said in a statement.
The company said it believes the odor is caused by trace amounts of chemicals called 2,4,6-tribromoanisole (TBA) and 2,4,6-trichloroanisole (TCA).
In October 2010, McNeil recalled roughly 128,000 bottles of the same caplets. In July 2010, McNeil announced a recall of 21 different product lots, including Children's Tylenol, Benadryl and Motrin.
And in the largest recall of children's medicine in history, Johnson & Johnson pulled more than 136 million bottles of Tylenol, Motrin, Zyrtec and Benadryl -- more than 40 products in all -- in April.
TBA comes from the breakdown of a chemical in wood pallets used to transport and store the packaging materials for the bottles.
According to ABC News Senior Medical Editor Dr. Richard Besser, the stomach problems some people experienced are not serious.
"They're not that severe -- we're talking about vomiting, diarrhea," Besser said after news of the December recall.
The recalled caplets were manufactured at the McNeil Consumer Healthcare plant in Fort Washington, Pa., before the company voluntarily closed the facility in April 2010.
McNeil also expanded a wholesale-level recall of other products it announced in January by 10 lots.
"That recall did not require any action by consumers or healthcare providers and was not undertaken on the basis of adverse events," McNeil said in the statement.
There have also been accusations of shady practices by the drug giant, including a "phantom recall," during which employees of a company hired by Johnson & Johnson were allegedly sent to buy affected Motrin off store shelves in lieu of a product recall.
In September 2009, a deputy commissioner at the U.S. Food and Drug Administration testified before Congress that the agency did not act quickly enough to stop the phantom recall.
Johnson & Johnson CEO Bill Weldon said at the time that he took responsibility for the company's multiple recalls.