Between 25,000 and 75,000 flowering plant species have been used in traditional medicine throughout the world. Only about one percent of these have been acknowledged through scientific studies to have real therapeutic value, though many are effective in producing a placebo effect. As many as 40,000 of the earth's 265,000 species of plants may have undiscovered medicinal value for humans. Many are already used by tribal healers, but this knowledge is unwritten and can be lost within a few generations.
Traditional medicine is still used by 70% of the African population. During the Gulf War, European doctors treated some wounds with a sugar paste that traces back to Egyptian battlefield medicine of 4,000 years ago. Most native cultures have systems of traditional medicine which are suppressed during the process of cultural invasion and domination, as has happened in many colonized countries and in Tibet under communist China.