"We tested green tea in combination with antibiotics against 28 disease-causing micro-organisms belonging to two different classes," Dr. Mervat Kassem of the Alexandria University in Egypt said in a statement. "In every single case green tea enhanced the bacteria-killing activity of the antibiotics."

Since green tea is already a popular beverage in Egypt, the researchers had set out to find out if drinking it would interfere with the action of the antibiotics. The discovery that the tea increased the medicine's effectiveness by making the bacteria more susceptible to the medicine -- surprised the researchers. In some cases even a low concentration of green tea was effective, the study said.

"Our results show that we should consider more seriously the natural products we consume in our everyday life," Kassem said. "In the future, we will be looking at other natural herb products such as marjoram and thyme to see whether they also contain active compounds, which can help in the battle against drug resistant bacteria."

The findings were presented at the Society for General Microbiology's 162nd meeting at the Edinburgh International Conference Centre in Scotland.