Muna L, Astirin OP, Sugiyarto. 2010. Teratogenic test of Pandanus conoideus var. yellow fruit extract to development of rat embryo (Rattus norvegicus). Nusantara Bioscience 2: 126-134. This experiment was performed to examine the effect of Pandanusconoideus Lam. var. yellow fruit extract on the percentage of the living foetus, the death intrauterus, heavy and long of foetus, foetusmorphology, and skeleton structur of foetus. The experiment was used by 25 pregnant mice that randomly were divided into 5 groups, they contained 5 mice. Each group was given with the different dose. The P1 group (control) was given 1 mL sesame oil, the group P2,P3, P4 and P5 were respectively given the yellow fruit extract 0,02 mL, 0,04 mL, 0,08 mL and 0,16 mL. The P. conoideus var. yellow fruit extract was given orally on day 5 to 17 of gestation (organogenesis periode). Observation was carried out on day 18 of gestation by caesarean section to take the foetus from the uterus. Foetus morphology was observed after taking foetus from uterus, whereas observation of skeleton structure was made wholemount preparat with dual colourization, they are Alcian blue and Allizarin Red-S. The result was analyzed with one way anova. Results showed that giving yellow fruit extract didn?t influence to the percentage of the living foetus, the death intrauterus, heavy and long of foetus. The effect of giving yellow fruit extract to the maternal were abnormality skeleton (lordosis) of foetus in the dose 0.16 mL and obstacled to the ossification of foetus.