The use of herbal medicines or natural health products as alternative medicines for public health use continues to expand rapidly around the world. Pre-clinical assays are essential to guarantee the efficacy and safety of natural products and are commonly requested by regulatory agencies to approve marketing of these products. Different animal models are used to evaluate the pharmacological effects of natural health products and herbal medicines in particular. The main toxicological assays and pharmacological activities to be tested in the evaluation of natural products will be discussed in this presentation. Common pharmacological effects of herbal medicines are: anti inflammatory, antioxidative, hepatoprotective, laxative and analgesic. The importance of using positive and negative controls will be explained and examples will be provided. Animal models currently used in the evaluation of herbal medicines will be presented and the importance of selecting the right model to reproduce human disorders will be highlighted.