Antique Prescriptions Law...?

I see many antique Prescriptions from the early 1900's.... They are up for auction and for sale all over the internet. I just wanted to make sure it was legal to buy some of these pieces of history... I dont want the DEA busting in my door. Shouldnt there be no problem and be considered an "antique"... I highly doubt i can get in trouble, just wanting some reurance