"Doctor, I have an ear ache."

2000 B.C. - "Here, eat this root."
1000 B.C. - "That root is heathen, say this prayer."
1850 A.D. - "That prayer is superstition, drink this potion."
1940 A.D. - "That potion is snake oil, swallow this pill."
1985 A.D. - "That pill is ineffective, take this antibiotic."
2000 A.D. - "That antibiotic is artificial. Here, eat this root!"