If you’ve ever wondered about how ancient cultures managed to take care of their teeth, new archaeological evidence may be able to shed some light on the issue. And it turns out that the ancient secret to cleaner teeth was a simple plant — something that we now consider to be a weed, in fact.

The plant, now known as “purple nutsedge,” has spread to over 90 countries and has seriously infringed upon the growth of approximately 50 different crops. The plant, given the nickname “the world’s worst weed,” is resistant to many pesticides and is nearly impossible to dispose of once it has taken root. However, purple nutsedge didn’t always have this bad reputation; in fact, ancient people living thousands of years ago actually incorporated the plant into their daily diet in order to fight plaque and gum disease.

Granted, Neanderthal communities living 2,000 years ago didn’t have the processed foods that wreak havoc on teeth today, but the grains produced by the earliest agricultural revolution fostered the growth of bacteria and acid accumulation on human teeth. It is likely that purple nuthedge was originally used as a medicinal herb before people discovered that regular consumption of the plant actually reduced tooth decay.

Scientists have recently begun excavating an ancient cemetery in the Sudan region, and analyses of teeth belonging to the ancient skeletons showed hardened bits of plaque containing remnants of purple nutsedge. Although archaeologists note that this evidence is the first indication that ancient people were aware of tooth decay, other archaeological findings in France have shown that Celtic communities were conscious of the aesthetic quality of their teeth, and even used a rudimentary type of dental implants. These techniques may not sound appealing compared to modern dentistry, but they certainly prove that your teeth are too important to be ignored.