Metabolomics is the systematic identification and quantification of all metabolites in an organism or biological sample. NMR has been used as a major application tool in plant metabolomics such as quality control, chemotaxonomy, and analysis of genetically modified plants. Herbal medicines are the important therapeutics and are used to manage common diseases such as cold, inflammation, pain, heart diseases, liver cirrhosis, diabetes and central nerve system diseases. Herb plants include various kinds of species such as geranium, mint, and thyme and so on and contain different kinds of metabolites. We performed NMR-based metabolomics study on the seven different species of herb plants using $^1H$ NMR experiments and OPLS-DA to understand the correlation between the classification of herb plants and their metabolite contents. This study showed clear metabolic discrimination among various herb plants. This metabolmics study found several diagnostic NMR signals which are able to be used as bio-markers for identification of the specific herb plants among various species. Clear metabolic discrimination of herb plants suggests three chemotaxonomic groups of herb species.