Hundreds of readers and viewers have reported pharmacy errors in the wake of an ABC News investigative report on what some fear is an unreported epidemic of such errors at large chain drugstores. "I had a similar experience at Walgreens in 2003," wrote Pam Koster from Littleton, Colo., in a comment on The Blotter Web site. At the time, Pam explained, her four-year-old son Michael had just been diagnosed with leukemia. After he had spent five days in the hospital, Pam brought Michael home and filled two prescriptions he needed for his treatment. THE BLOTTER RECOMMENDS Blotter Results of the ABC News ’20/20′ Undercover Pharmacy Investigation Photos Unreported Pharmacy Errors 20/20 Video Pharmacy Errors: Unreported Epidemic? Click Here to Check Out Brian Ross Slideshows That night, as Pam prepared to give Michael his first doses of the medications, she read the directions from the bottles and thought something was odd, she told ABC News. "I said, ‘This doesn’t seem right,’" Pam said she recalled. Checking with the local children’s hospital, she says her fear was confirmed: the pharmacy had mixed up the instructions on Michael’s medications, advising Pam to give her son a much larger dosage of a powerful drug, Dexamethasone, than the hospital had directed and to give him much less of a second drug, Methotrexate, which was key to curing his leukemia. Click Here for Full Blotter Coverage. "I went to Walgreens the next day, first thing in the morning," Pam told ABC News. "The pharmacist who filled the prescription was there. I asked to talk to him specifically. I showed him the labels and said, ‘This isn’t right. I want you to pull what the hospital called in and show me what you did.’" According to Pam, the pharmacist said he did not have the paperwork handy but would look into the matter. At first she resisted, Pam said, but eventually gave in after being promised the store would call her later that day with more information. The pharmacist’s supervisor called her that afternoon, Pam told ABC News. Pam says she admitted the error and vowed to bring it up at the store’s next staff meeting. "We all make mistakes in our jobs," says Pam, whose disturbing story was one of dozens posted to ABCNews.com in response to the "20/20" investigation into pharmacy errors. "But there’s got to be some sort of way these things can be reported. I’d like to be able to go to a [W]eb site and [look up] this Walgreens," Pam says, or even a specific pharmacist there, "and see what their track record is in terms of errors." Walgreens has declined to address any specific incident of alleged pharmacy error. In a statement last week in response to the ABC News "20/20" investigation, Walgreens said, "We deeply regret the few errors that have occurred among the more than 500 million prescriptions we fill each year at our 5,600 pharmacies." Improving wages for pharmacy technicians and increasing their training and credentialing requirements would also cut down on errors, some readers said. Lori L., who interned at a chain pharmacy in Nevada, urged Americans to make their voices heard if they want to help raise awareness. "Unless people speak out, nothing will change and errors will continue to be made by uneducated, undedicated techs who should not be in the profession," Lori wrote in her comment on The Blotter. She told ABC News she became convinced for the need to fix the system after catching multiple errors made by pharmacy techs at a chain store where she helped out as an intern. "I was still theoretically a student," Lori told ABC News, "[and] I caught errors that supposedly experienced techs were making." Of pharmacy technicians, Mary Ann Wagner, senior vice president of the National Association of Drug Store Chains, said, "We depend on them very heavily in our industry," saying there is no problem relying on technicians if they are adequately trained.