Lysergic acid diethylamide, also known as LSD, wasn't invented by accident. Yet the effects of one LSD derivative were discovered perchance. (Read How LSD Works to learn more about the drug's history.)
When Swiss chemist Albert Hofmann began working for Sandoz laboratories in 1929, he was on a mission to map the unchartered territory of compounds derived from a fungus called ergot. Hofmann wanted to examine the properties and stability of these compounds to gauge their potential as medicine.
He produced one derivative called LSD-25, but the compound wasn't particularly interesting to other scientists and physicians at the time.
Five years later, Hofmann decided to look at LSD-25 once more. While producing the compound in 1943, Hofmann claimed he was "interrupted in [his] work by unusual sensations" [source: Hofmann]. Hofmann somehow accidentally ingested the substance, placing him in an intoxicated and stimulated state. After leaving work early to go home and lie down, Hofmann claimed to perceive "fantastic pictures" and shapes with "intense kaleidoscopic play of colors" [source: Hofmann].
Hofmann had accidentally discovered the effects of one of the strongest psychic drugs in modern times. Although Hofmann experimented further with the drug and pushed for its use in medical and psychiatric settings, he was not thrilled to learn that people were abusing the drug recreationally in the 1960s. As a result, he resorted to calling LSD his problem child.
Our next accidental invention relies on forgetfulness.
The Supernatural or Poisoning? Looking back, historians have applied our present knowledge of the fungus ergot to periods of reported supernatural events, hysteria and poisoning in the past. Reported in farming communities across Europe during the Middle Ages, ergot, which grew on rye, contaminated food and produced a lengthy list of negative side effects when consumed continually. Symptoms include tingling and burning of the limbs, muscle pain, diarrhea, "impaired mental function" and gangrene, to name a few [source: Merhoff and Porter]. Scholars even debate that the hysteria and supernatural claims made during the Salem Witch Trials of 1692 may have been caused by members of the town unknowingly consuming bread tainted with ergot.