Traditional remedies such as tea and honey help in the fight against resistant superbugs, say scientists.
The more the drugs that are used, the more likely it is that any bacteria will build up a resistance to them, leading to what one expert called an "arms race" that he feared was being lost.
"I hate to say we're heading back towards the pre-antibiotics days when treating serious diseases was extremely problematic," the Telegraph quoted Professor Les Baillie, of Cardiff University, as telling the BBC.
Professor Baillie is leading a team that is looking into whether old-fashioned cures such, as tea and honey, could be the next way to take on superbugs.
Tea contains compounds called polyphenols that have health benefits including their ability to kill micro-organisms.
Scientists from Prof Baillie's team have been looking at tea as a source of drugs to treat clostridium difficile - a bacterium that was responsible for at least 2,000 deaths and more than 24,000 infections last year.
Rhidian Morgan-Jones, a Cardiff-based surgeon, said that there were real concerns about the future of medicine on a post-antibiotic age.
"You're going back to the last century where before antibiotics all you had to do was lance boils, drain the puss and put people in bed and rest them. Some you cured and some you didn't," he said.