Developments of drugs or natural products from plants are possibly made, simple to use and lower cost than modern drugs. The development processes can be started with studying local wisdom and literature reviews to choose the plants which have long been used in diverse areas, such as foods, traditional medicine, fragrances and seasonings. Then those data will be associated with scientific researches, namely plant collection and identification, phytochemical screening by gas chromatography-mass spectrometry, pharmacological study/review for their functions, and finally safety and efficiency tests in human. For safety testing, in vitro cell toxicity by cell viability assessment and in vitro testing of DNA breaks by the comet assay in human peripheral blood mononuclear cells can be performed. When active chemicals and functions containing plants were chosen with safety and efficacy for human uses, then, the potential medicinal natural products will be produced. Based on these procedures, the producing cost will be cheaper and the products can be evaluated for their clinical properties. Thus, the best and lowest-priced medicines and natural products can be distributed worldwide.