The new information was revealed in a congressional memo.
In April, 40 varieties of children's cold medicines were recalled, including infant Tylenol, Benadryl and Motrin.
Since then, the Food and Drug Administration has received hundreds of reports of problems, including seven deaths.
The FDA is investigating whether the problems are linked to flaws in the products, but say so far it has not determined a direct link.
FDA inspectors and Johnson and Johnson executives will testify at a congressional hearing Thursday.