Hyper Eth-iodine was a medicine, a general anaesthetic. Its effects also included reducing chances of secondary infection and helping a patient sleep.
In 1873, the Eighth Doctor gave it to Count Rolf Wittenmeier in Vienna, Austria after the Count's eye was gouged out by Gramm, a Cyberman from Mondas. The Doctor noted that administering this medicine was temporally unethical suggesting that it originated from the future. (AUDIO: The Silver Turk)