Mums (chrysanthemums) are poisonous to humans as well as to pets. All parts of the chrysanthemum plant contain toxins, primarily pyrethrins and sesquiterpene lactones. In humans, ingestion can cause symptoms such as vomiting, diarrhea, stomach pain, excessive salivating, and lack of coordination. Additionally, direct contact with chrysanthemums can cause allergic skin reactions and respiratory issues in sensitive individuals, including itching, burning, and irritation. Inhalation of chrysanthemum pollen may worsen respiratory conditions like asthma. Severe allergic reactions are rare but possible.
Thus, while mums are not usually fatal, they are definitely toxic and can cause unpleasant and sometimes serious health effects if ingested or if there is significant exposure to the plant. Care should be taken especially around children and pets to avoid ingestion or contact with chrysanthemums.