'Bitter' in the Bible

The name of the star is called "Wormwood." One third of the waters became wormwood. Many people died from the waters, because they were made bitter.

I went to the angel, telling him to give me the little book. He said to me, "Take it, and eat it up. It will make your stomach bitter, but in your mouth it will be as sweet as honey."

I took the little book out of the angel's hand, and ate it up. It was as sweet as honey in my mouth. When I had eaten it, my stomach was made bitter.