A method utilizing Drosophila-melanogaster-fruit-flies for screening chemicals for teratogenicity was described. For each sample five male and five virgin female Oregon-R-Drosophila-flies were placed in a 30 milliliter (ml) cotton stoppered shell vial containing 2.5 grams of fresh intact Drosophila medium to which 7.5ml fresh distilled water was added. All chemicals to be tested were weighed and added directly to the distilled water during media preparation. All vials were maintained at 25 degrees-C and 60 percent relative humidity. The flies were allowed to mate. The larvae that hatched from the eggs fed on the media and metamorphosed into adult flies in about 9 or 10 days. The adult flies were systematically examined for external morphological abnormalities under a binocular microscope. The method was evaluated using test chemicals of which results are reported for bisphenol-A (80057), diethylene-glycol-monobutyl-ether (112345), N,N-dimethylacetamide (127195) (NNDMA), ethylene-glycol- monomethyl-ether (109864) (EGMME), ethylene-glycol-monoethyl-ether (110805) (EGMEE), niacin (98920), thymidine (50895), dimethyl- sulfoxide (67685) (DMSO) and sodium-heparin (9005496). The highest incidence of bent bristles was seen with NNDMA and DMSO, which induced 40.4 and up to 70 percent incidences of bent bristles, respectively. Humoral bristle defects occurred with a 59 percent incidence in DMSO treated flies and a 4 percent incidence in EGMEE treated flies. Flies treated with sodium-heparin displayed unique abnormalities including humeral knobs, multiple and missing halteres and the fusion of front leg segments. Wing notches, rarely seen in control flies, were found in 3, 14, 15 and 18 percent of flies treated with NNDMA, EGMME, EGMEE, and DMSO, respectively. The authors conclude that Drosophila flies give significant and reproducible responses to a variety of chemicals. Validation studies, however, will be necessary before the system can be incorporated into existing teratologic screening methods.