All available lots of Tylenol Arthritis Pain Caplet 100-count bottles, packaged with a distinctive red cap, are being recalled, the drug's maker said.
The move expands an earlier partial recall of the product in November, when five lots were called back after consumers complained of an "unusual moldy, musty, or mildew-like odor," McNeil Consumer Healthcare said in a press release.
It's also the second recall of Tylenol products in two months; a kids' formulation was recalled in September.
In the arthritis medication, the odor was associated with nausea, stomach pain, vomiting and diarrhea, the company said, adding that the expanded recall is a precaution. McNeil makes other Tylenol arthritis products, and those medications remain on sale.
The company said the odor is caused by a compound known as 2,4,6-tribromoanisole, which has been linked to musty odors in other food products as well as wine.
The effects of the compound have not been well studied, the company said, but all reported adverse events so far have been "temporary and non-serious."
The source of 2,4,6-tribromoanisole is believed to be the breakdown of a chemical used to treat wooden pallets that transport and store packaging materials.
The recall of the arthritis formulation comes after the company recalled several lots of pediatric Tylenol liquid products made between April and June, 2008.
The company said it was recalling the drugs because "during this period, an unused portion of one inactive ingredient did not meet all quality standards."
While the current recalls are apparently not associated with any serious adverse events, Tylenol was at the center of a horrific story in 1982, when seven people died after taking capsules that had been poisoned.
The poisonings took place in the Chicago area and involved Extra-Strength Tylenol medicine capsules that had been laced with potassium cyanide.
No one was ever convicted in the poisonings, and the case remains unsolved but the affair led to reforms in the packaging of over-the-counter substances.
During the incident, the company recalled all Tylenol products -- a reported 31 million bottles with a retail value of over $100 million.
In the current recall, McNeil Healthcare said consumers should stop using the medication and contact the company about how to dispose of or return the product.