In a groundbreaking discovery, scientists have found chemical traces of betel nut chewing in 4,000-year-old teeth from a Bronze Age burial in Thailand -- the earliest direct evidence of psychoactive plant use in Southeast Asia.By analyzing hardened dental plaque, researchers uncovered compounds linked to betel nut, a stimulant that boosts alertness and euphoria...One common side effect of regular chewing is teeth stained a deep reddish-brown or black.However, the absence of these stains does not necessarily mean the habit was avoided. A recent investigation by an international team used a cutting-edge technique to study ancient dental plaque from Bronze Age Thailand,...