According to the Wikia for Once Upon a Time: http://onceuponatime.wikia.com/wiki/A_Bitter_Draught In the episode, the Queen says to Monte Cristo: "The venom of the Agrabahn Viper. A bitter draught; slow and painful." Obviously, the venom is poison. It is also, for the Queen, a solution or a medication to take care of her problem (whomever she is trying to kill). In this quotation, the literal meaning is: A measured portion of a liquid or aerosol medication; a dose. from: http://www.dictionary.com/browse/draught a dose of liquid medicine from https://www.vocabulary.com/dictionary/draught The phrase presumably comes from a line in Alexandre Dumas' book The Count of Monte Cristo: "Hatred is blind, rage carries you away; and he who pours out vengeance runs the risk of tasting a bitter draught." i.e. a person who seeks vengeance may receive harmful, unintended consequences. In this quotation, the literal meaning is a serving of drink (usually alcoholic) drawn from a keg from: https://www.vocabulary.com/dictionary/draught Bitter in this case meaning it has gone bad Both definitions are related. In any case, a bitter draught contextually means a harmful, imbibed substance. As a title it can be interpreted as "a dastardly solution", or more literally as referring to the poison.

Difficult without having context as the word Draught has multiple meanings... It could be cool air moving through a room for example "there is a bitter draught coming from the window or door" Draught in english also refers to a beer or cider on tap (as apposed to in a bottle) and bitter is a type of beer, so could be relating to this.

a severe famine