plants
herbs
lichens
all of these are studied by botanists
Trial and error
Local doctor
Watching animals
mountain tops
jungles
oceans
your back yard
everywhere
Aspirin
Willow Bark
Both of these.
Neither of these.
100
200
300
400
Cranberry
Curare
Dandelion
Willow
Artemisia Annua
Sweet Annie
25
50
75
20
40
60
80