One dose of an Antidote will remove all lasting effects in the Alteration effect group (Enfeeble, Hallucinate, Intoxicate, Paranoia). It does not matter how those effects were caused.
Example: Finther is hit by an Enfeeble gas thrown by his enemy Vorin. He sits on the ground and plays with daisies, roleplaying that his mind is unable to focus. While he is on the ground, a ghoul hits him for “3 Enfeeble.” He is now vomiting while playing with daisies. Finally, someone throws a Paralysis spell at him and he becomes paralyzed. Darlissa runs over and feeds Finther an Antidote. Both the Enfeebles are removed; however, this does not cure the damage caused by the weapon nor does it remove the Paralysis, since that effect is not in the Alteration group.