"We tested green tea in combination with antibiotics against 28 disease causing micro-organisms belonging to two different classes," says Dr Mervat Kassem from the Faculty of Pharmacy at Alexandria University in Egypt. "In every single case green tea enhanced the bacteria-killing activity of the antibiotics. For example the killing effect of chloramphenicol was 99.99% better when taken with green tea than when taken on its own in some circumstances."

Green tea also made 20% of drug-resistant bacteria susceptible to one of the cephalosporin antibiotics. These are important antibiotics that new drug resistant strains of bacteria have evolved to resist.