The drops can be considered a type of poison or blessing in Rowena's life, as they were placed by an unknown individual and caused her death.
Although you haven't shown the story this question refers to, we can say from the context of the question that it refers to "Ligeia" written by Edgar Alan Poe.
About "Ligeia" we can say that:
This is a short story that shows a narrator in love with Ligeia, a beautiful and intelligent woman.
The narrator, however, marries Rowena, a woman he does not love and does not intend to love.
Ligeia dies throughout the story, which leaves the narrator extremely depressed and violent.
Rowena is very afraid of him and lives miserable, trapped in a loveless marriage. This deteriorates her health very badly.
When Rowena is agonizing in her bed, a mysterious and invisible individual drops red drops into the glass that Rowena goes to have a drink from.
These drops cause Rowena's death.
In this case, the drops can be seen as a poison, which took Rowena's life, or as a blessing, as it brought peace to her soul.
The mysterious individual can be interpreted as the spirit of Ligeia, who wished to free Rowena from her suffering, or as the narrator who caused Rowena's death as a way of getting rid of her presence.
Based on this, we can see that Poe wanted to convey a very strong message through the short story. This message showed that love is such a strong and overwhelming feeling that it can create terrible and frightening situations.
