Abstract: Plants of Celosia argentea var. spicata were treated with 0, 1000, 2000, 3000 and 4000 ppm. Dimethyl Sulphate (DMS) solution as soil drench to study the effect of DMS on the plant growth and phytochemical composition. Also, to produce new patterns of vegetative and flowering growth and identify them using Inter Simple Sequence Repeat (ISSR) markers. The concentration of 3000 ppm increased significantly the number of leaves, concentration of anthocyanin in the leaves and inflorescences in both generation and the concentration of phenols in the M2-generation. The treatments of 1000, 2000 and 3000 ppm increased significantly the concentration of alkaloids in the M2 generation. All treatments decreased significantly stem diameter, length of the inflorescence, delayed flowering in both generations and decreased plant height in the M1-generation and chlorophyll content in the M2 generation. Changes of leaf and inflorescence shape were found in the M2 generation. The treatment of 3000 ppm produced one plant with bigger growth in the M2 generations. Dwarfed plants were also obtained after treatments of 2000, 3000 and 4000 ppm. Plants with green vegetative growth, yellow nods and lacks of anthocyanin pigments were produced in the M1 generation after the treatment of 3000 ppm and inherited in the next generation. The percentage of polymorphism of the amplified products was 41.8%. UPGMA dendrogram program classified the samples into two large clusters. The control sample was grouped in cluster I and the five mutants were grouped in cluster II.