TRENTON, N.J. (AP) — Sales of Johnson & Johnson pain relievers are collapsing as a string of recalls appears to have made consumers wary of once-sterling brands such as Tylenol and Motrin.

An eighth recall, announced Thursday could worsen consumer reaction. That wariness and the huge amount of products pulled off store shelves together look to be costing J&J tens of millions of dollars a month.

Thursday’s recall by Johnson & Johnson’s McNeil consumer health care unit covers 21 lots of products, including Children’s Tylenol.

The string of recalls is an embarrassment for a company that set the standard on how to do it correctly when it rushed to pull bottles of Tylenol — deliberately poisoned by someone who was never caught — off store shelves in the early 1980s.

This time, the culprit appears to be a lack of internal quality control. That’s harder to forgive, particularly given that the public has little tolerance for mistakes or carelessness involving products for children, said analyst Steve Brozak of WBB Securities.