Taraxci Herba is in use in eastern medicine. The eastern medical doctors use Taraxci Herba for clearing away heat and eliminating toxin (淸熱解毒), inducing diuresis for treating stranguria (利尿通淋), etc. We investigated toxicity, symptoms of poisoning or side effect, poisoning treatment and prevention against poisongin and side effect of Taraxci Herba. The results were summarized ad follows: 1. The poisoning symptoms or side effects from Taraxci Herba occasionally are revealed. Those are mainly stimulating symptoms on gastrointestinal system and allergic reaction on the skin, etc. 2. If the patient has poisoning reactions or side effects, the patient should stop taking medicine of Taraxci Herba. In that case, the poisoning reactions or side effects will be disappeared. 3. In order to prevent against poisoning or side effect of Taraxci Herba, the patients should keep usage, dosage and notes.