Can antibiotics cause a weak erection?

Don't think so. But getting sick enough to require antibiotics can certainly take the wind out of your sail. Give yourself time to fully recover from your illness. At that point in time, if you're still noting issues w/your erection, then it's time to get checked out by your family physician. Perhaps this was just coincidental & your erections have been getting weaker w/time? Maybe illness just put you over edge?