Penicillin can be dangerous past its expiration date. Not sure how long past, but I’ve heard that’s true for that medicine at least.
YUP!
Took some penicillin from a drug store pharmacy after a tooth extraction. Got violently sick in less than an hour...while driving! Dentist wanted the unused pills. He took them to the hospital he worked at (Columbia Presbyterian, NYC) to have them tested. He said they were old and he raised hell with the pharmacy.