movie where a boarding house of girls is accidently given an aphrodesiac

A headstrong young teacher in a private school in 1930s Edinburgh ignores the curriculum and influences her impressionable 12-year-old charges with her over-romanticized worldview.

Muriel Spark's classic novel The Prime of Miss Jean Brodie was adapted by Scottish Television into a seven episode television serial for ITV in 1978 that featured Geraldine McEwan in the lead role. From Wikipedia.