ONE THING Papua New Guineans and Indians have in common is addiction to betel-nut chewing. Crimson mouths and red spit-splattered walls are common in PNG.

Papua New Guineans chew a potent mix of green betel nut and powdered slake lime, combined with the Piper betel plant. With deadly consequences. Oral cancer is prevalent and evidence suggests betel chewing is to blame, not tobacco.

Steven J Thomas and Robert MacLennan reported in The Lancet that tumours are significantly linked with slaked lime. The researchers concluded that lime is the culprit -- not the betel nut. They suggest lowering the calcium hydroxide content of the lime as a low-cost strategy for preventing cancer