[In the Old Testament] it is suggested that it is a poison derived from a root of some kind (Deuteronomy Deu. 29:18), that it is very bitter (Proverbs Pr. 5:4), and that it produces drunkenness (Lamentations Lam. 3:15) and eventual death. It is associated with another poison known as gall (Deuteronomy Deu. 29:18; Lamentations Lam. 3:19). This substance was used to produce a stupefying drink for Christ on the cross (Psalm Ps. 69:21; Matthew Mat. 27:34) which, however, He refused to drink.4Significantly, God describes idolatry as a root bearing bitterness of wormwood (Deu. Deu. 29:17). Idolatry is a prevalent sin of the earth dwellers during this time of judgment (Rev. Rev. 9:20+; Rev. Rev. 13:15-16+). So God judges their bitterness of wormwood by giving them wormwood to drink. This is the same judgment which God gave Israel when she rejected Him and pursued false Gods (Jer. Jer. 8:14; Jer. 9:14-16; Jer. 23:15). Wormwood also describes the fruit of unrighteousness, which will be a prevalent characteristic of the Tribulation period (Amos Amos 5:7; Amos 6:12 cf. 2Ti. 2Ti. 3:2-4). At the bitter waters of Marah, Moses cast a tree into the waters and made them sweet (Ex. Ex. 15:25). This pictured Messiahs work on the cross which provided living water (John John 7:38-39). Here, we have wormwood which turns the earth dwellers water bitter. Since they would not avail themselves of the cross of Christtodays tree of lifeto obtain the living waters of Jesus (John John 4:10), God gives them wormwood instead and poisonous waters which bring death rather than life. Like Moses, one of Elishas miracles healed bitter waters and made them sweet (2K. 2K. 2:19-22).
1 Henry George Liddell, Robert Scott, and Henry Stuart Jones, A Greek-English Lexicon. With a revised supplement, 1996., With a revised supplement, 1996 (Oxford, England: Oxford University Press, 1996), 299.
3 James Swanson, Dictionary of Biblical Languages With Semantic Domains : Hebrew (Old Testament), electronic ed. (Oak Harbor, WA: Logos Research Systems, 1997), s.v. a very unpleasant substance to consume, which may make one sick, either a root herb, leafy plant oil, or liver-bile; wormwood, i.e., a dark green bitter oil used in absinthe .