The plant Artemesia absinthium (or “wormwood”) is mentioned several times throughout the Bible. Solomon writes that the adulteress is as “bitter as wormwood” (Prov. 5:4).
Likewise, Moses compares idolatry and serving other gods as “a root bearing poisonous fruit and wormwood” (Deut. 29:18; c.f. Jer. 9:15; 23:15; Lam. 3:15, 19). Osborne explains that the taste of wormwood “is so potent that one ounce of it can still be detected in 524 gallons of water!”[1] Wormwood itself is not poisonous, but it probably is symbolic of the fact that the people have made a horrible, bitter decision to fall under the judgment of God.
[1] Osborne, Grant. Revelation. Baker Exegetical Commentary on the New Testament. Grand Rapids, MI: Baker Academic. 2002. 354.
“And the name of the star is called Wormwood: and the third part of the waters became wormwood; and many men died of the waters, because they were made bitter. (Rev 8:11)”
