Lithospermi Radix is in use in oriental medicine. Oriental medical doctors use Lithospermi Radix for clearing away heat and eliminating toxin(淸熱解毒), etc. We investigated toxicity, poisoning symptoms, poisoning treatment and prevention against poisoning of Lithospermi Radix. The results were summarized as follows: 1. Taking Lithospermi Radix excessively cause diarrhea, etc. 2. In order to prevent against side effects of Lithospermi Radix, the patients should keep usage, dosage and notes.