Painkiller found in human saliva
Natural-born painkiller found in human saliva - health - 13 November 2006 - New Scientist
When the researchers injected a pain-inducing chemical into rats’ paws, 1 gram of opiorphin per kilogram of body weight achieved the same painkilling effect as 3 grams of morphine.
3 grams of morphine per kilogram of body weight? At that dose it would take about 4 oz of morphine to dull my pain. Think maybe they mean milligrams? A quick google tells me that a typical dose of morphine for an adult is 4-10mg intravenously.