The different colours that we visualize through our Eyes, the diverse odours that are sensed by the olfactory system of our Nose and the six sorts of basic tastes that are recognized by the taste buds of our Tongue, when we study the plant parts such as roots, stems, barks, leaves, flowers, fruits, seeds etc. are mainly due to the chemical constituents that are present in plants/plant parts. The Colour, Odour and Taste that are recorded from drug plants/plant parts through Organoleptic studies (one of the pharmacognostic parameters), are in fact the baseline information, based on which one can proceed further for a preliminary/detailed phytochemical and pharmacological screening in any plant/plant part. To highlight the importance of the above-mentioned features, a new system (COT system) has been proposed. COT is a three-letter acronym, which refers to Colour, Odour and Taste of the drug plants that could be used to figure out the nature of chemical compounds and their possible  pharmacological activities.