I ran across this online somewhere and had to chuckle.
2000 B.C. – Here, eat this root.
1000 A.D. – That root is heathen. Here, say this prayer.
1850 A.D. – That prayer is superstition. Here, drink this potion.
1940 A.D. – That potion is snake oil. Here, swallow this pill.
1985 A.D. – That pill is ineffective. Here, take this antibiotic.
2000 A.D. – That antibiotic is artificial. Here, eat this root.
This is true, yes?