The Andromeda Strain
In 1971, the two most family-friendly ratings were "G" and "GP." GP just meant, "Content not suitable for pre-teenagers," so it can be thought of as a precursor to the modern PG-13 rating. As such, films such as Snow White and The Aristocats were rated the same as the morbid film The Andromeda Strain. In the first half-hour or so, alone, the film contains several swears ("damn" and "hell"), drug references, a topless dead woman, and a corpse being cut into. It's still not as traumatic as the forest scene from Bambi, though.