reporter: shaman pascuala diaz ends the spiritual cleansing with a soft drink. t not coca-cola, she says. pascuala: a lot of people only drink coca-cola, but too much sugar isn't good for them. reporter: but the pineapple soda also contains sugar. the road back to healthy eating is long, and kicking bad habits is the hardest part. reporter: for centuries, legendary medicine men, the kallawaya, lived close to lake titicaca. they were the doctors of the incan kings, often called witches of the andes. what remains of this culture today? we met aurelio ortiz, who calls himself one of the last kallawaya. aurelio: we kallawaya know the medicinal properties of roots, flowers, leaves, and fruits. i received my extensive knowledge about plants from my grandparents. look at this moss. you can cure many people who have been put in psychiatric wards with it. in traditional western medicine, you just call these people crazy. reporter: aurelio also has remedies for alzheimer's and cancer, but he won't tell us exactly which ones. a patient from the capital city of la paz has ar