Pharmacology of Silymarin

F. Fraschini, G. Demartini, D. Esposti,


Clin Drug Invest. 2002;22(1) 

In This Article

3. Toxicity

The acute toxicity of silymarin has been studied in mice, rats, rabbits and dogs after intravenous infusion. The 50% lethal dose (LD50) values are 400 mg/kg in mice, 385 mg/kg in rats and 140 mg/kg in rabbits and dogs. However, these values are only approximate, as they depend on the infusion rate. When the compound is given by slow infusion (over 2 to 3 hours), values of 2 g/kg may be recorded in rats. After oral administration tolerance is even higher, with values over 10 g/kg. In the event of acute intoxication, the cause of death seems to be cardiovascular failure.[3] Similar results have also been obtained by Vogel et al.[5]

Other experiments to assess the acute toxicity of silymarin were performed in beagle dogs, rabbits, Wistar rats and NMRI mice after an intravenous bolus dose. Silymarin was used as the hemisuccinate sodium salt and the animals were kept under observation for 14 days. The LD50 was 1050 and 970 mg/kg in male and female mice, respectively, and 825 and 920 mg/kg in male and female rats, respectively. The mean lethal dose for rabbits and the maximum tolerated dose in dogs were calculated to be about 300 mg/kg.[6]

These data demonstrate that the acute toxicity of silymarin is very low. Similarly, its subacute and chronic toxicity are very low; the compound is also devoid of embryotoxic potential.[33]


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