Parents and investors may both be worried by this weekend's recall of dozens of versions of Children's Tylenol and several other infants' and children's medications made by Johnson & Johnson's McNeil Consumer Healthcare division.

Three days after the recall late Friday, the stock market appeared to reflect little concern. Johnson & Johnson's share price rose 1.6 percent - more even than Monday's rise in the Dow Jones industrial average, of which J&J is one of 30 component companies.

But parents voiced fears to pediatricians and pharmacists, and asked questions about the affected products - two dozen formulations of Tylenol, known generically as acetaminophen, along with liquid formulations of Motrin (ibuprofen), Benadryl (diphenhydramine), and Zyrtec (cetirizine).

So far, the advice for parents, at least, is clear: McNeil says they should stop using any of the affected products - essentially, any liquid formulation of those medications made by McNeil, which is based in Fort Washington.

Doctors and pharmacists recommend that parents replace the medications with generics of the same drugs or other brand-name versions, none of which are affected by the recall. Consumers can obtain refunds directly from McNeil or from at least some pharmacies.

Here are answers to some key questions:

What went wrong? Little is known. McNeil, in announcing the voluntary recall late Friday "in consultation with the U.S. Food and Drug Administration," says some of the products "may not meet required quality standards."

McNeil says the children's products may have "a higher concentration of active ingredients than is specified." They may also have contaminants that spokesman Marc Boston describes as "solidified product ingredients or manufacturing residue, such as tiny metal specks." He declined to say what metal or metals had been found.

Nor is it clear if McNeil is responding with an abundance of caution or faces greater concerns.

"They've had a lot of problems," says Don Mays, senior director of product safety for Consumer Reports. "It seems like they need better quality control and process control in the manufacture of these products."

This is the second major recall of children's Tylenol products in the last year. In September, more than 20 versions were recalled because of possible bacterial contamination.

Was there a danger to my child? It's impossible to say for sure, but McNeil is suggesting not.

"We have received consumer inquiries," Boston says. "But I can confirm that the recall is not being undertaken on the basis of adverse medical events" reported to the company.

Nor has the FDA so far suggested otherwise.

"While the potential for serious health problems is remote, Americans deserve medications that are safe, effective, and of the highest quality," FDA Commissioner Margaret A. Hamburg said in a statement Saturday. "We are investigating the products and facilities associated with this recall and will provide updates as we learn more."

By contrast, when McNeil voluntarily recalled some related products in January because of a contaminant it said caused "an unusual moldy, musty, or mildew-like odor," the company acknowledged "a small number of cases" of reactions such as nausea, stomach pain, vomiting, or diarrhea.

What if I'm worried? David Pollack, a Children's Hospital pediatrician and senior physician at the hospital's Care Network in Delaware County, says parents should report any concerns to their pediatrician, who will then notify the FDA and McNeil.

Based on the information available, Pollack said, "I could certainly believe that there's been no adverse effects on kids."

Can you substitute an adult version? Pollack and McNeil both warn against doing this, even with older children who can swallow pills, because of the danger of incorrect dosages.

"Every day we're faced with a misdosage when a mother is trying to convert an adult dosage to her kids," Pollack says. "If it's not really designed for children, we would tell them not to use it."

So what are the alternatives? Doctors and pharmacists say generic versions are widely available and considerably less expensive. "I use them all the time for myself and my family," says Paul Tirotto, owner of Broad Street Apothecary in South Philadelphia.

For more information on the recall or how to obtain a refund, go to

www.mcneilproductrcall.com. You can also call 1-888-222-6036, but the company says it has been overwhelmed with calls and may not be able to answer.

Contact staff writer Jeff Gelles at 215-854-2776 or jgelles@phillynews.com.