Poison in a dream is read as something harmful taken in without noticing — a toxic influence, a resentment, an idea that slowly does damage. Dream books ask what has been quietly souring your days.
Has this come up in your dreams before? What was going on in your life then?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.