"A Short History of Medicine:
2000 BC: Here, eat this root.
1000 BC: That root is heathen, say this prayer.
1850 AD: That prayer is superstition, drink this potion.
1940 AD: That potion is snake oil, swallow this pill.
1985 AD: That pill is ineffective, take this antibiotic.
2000 AD: That antibiotic is artificial. Here, eat this root."