Present investigation is to identify the morphological character and poisonous effect of selected but commonly available plants in Dhoni forest, Palakkad, Kerala. A total of 6 plants were mentioned along with vegetative and floral characteristics, poisonous plant parts, chemical constituents, side effects. Poisonous plants in small quantities itself can cause harm to living organisms. Defence mechanism in plants have morphological, physiological or chemical measures which help them to protect and deter the herbivores. The toxic chemical substances include proteins, oxalates, glycosides, terpenes, phenolics, alkaloids, anthocyanins, etc. Still poisonous plants too are used for various ailments due to wide number of phytochemical constituents present in it.