The terrible, nightmarish quality of a Toxic Dream can signal that your body, emotions, or mind were in a toxic state at the time of the dream.
This type of dream can result from a number of factors from earlier in the day, including: eating refined carbohydrates (sugar, white flour, etc.), processed or junk food, or additives or preservatives; eating too much too close to bedtime; ingesting drugs or other substances that tax the body; encountering environmental toxins (mold, exhaust fumes, etc.); physical, emotional, or mental stress; toxic feelings (such as going to bed angry); not resting your body and mind enough during the day.