This ad was aimed at persuading physicians to prescribe the histamine-receptor antagonist, Zantac, for patients suffering from reflux oesophagitis (heartburn).
It is based on the insight that physicians would initially advise patients to raise the head-end of their beds slightly, so that gravity could keep stomach acid where it belongs... in the stomach.
And, if that didn't work, they would advise patients to raise the bed angle even more.
This idea takes that thinking to it's logical conclusion, by standing the bed completely on its end.
Alternatively, physicians could simply prescribe Zantac.