A short history of medicine:
2000BC Here, eat this root.
1000AD That root is heathen. Here, say this prayer.
1850AD That prayer is superstition. Here, drink this potion.
1940AD That potion is snake oil. Here, swallow this pill.
1985AD That pill is ineffective. Here, take this antibiotic.
2000AD That antibiotic doesn't work anymore. Here, eat this root.