Science makes man free from false-beliefs and superstitions. Biology or life science is the science dealing with the study of living organisms namely plants and animals. To live active and effective in life, it is absolutely necessary that we remain healthy and free from hazards of ill nutrition and diseases. Higher secondary school curriculum described a few number of indigenous plants with many therapeutic uses. Now a days the students of new generation are not aware of it and also not many reference books are available to study in detail all the indigenous plants required for them. So the investigator tries to prepare an instructional package which is helpful to the students, teachers. The main objective of the study was to test the effectiveness of an instructional package by comparing the Pre test and Post test Achievement scores in morphology and therapeutic uses of indigenous plants of the treatment group. The method adopted in the present study is Experimental Method. The experimental design adopted in the present study was single group ‘Pre-Test Post- Test’ design. In the present study, the sample consisted of 60 students from different higher secondary schools in Kerala. The findings of the study revealed that the instructional package developed by the investigator is more effective for enhancing the Achievement in morphology and therapeutic uses of indigenous plants among Higher Secondary School students.