Aspirin
From Tardis Wiki, the free Doctor Who reference
Aspirin was a drug used by Humans in tablet form to relieve mild pain. It was a fatal poison to Time Lords, as their metabolism was different. (DW: The Mind of Evil)
In 1555, Francois de Noailles accused Evelyn Smythe of plotting to use the aspirin she brought with her to poison Queen Mary. (BFA: The Marian Conspiracy)
In 1979, Professor Chronotis offered Chris Parsons some aspirin for his headache. (DW: Shada, WC: Shada)
By the 25th century, aspirin was no longer used. Barbara Wright got some aspirin from the TARDIS's first aid kit for Vicki's headache. (DW: The Web Planet) Later, the Doctor no longer carried aspirin in his TARDIS. (EDA: The Infinity Race)
