The occurrence of stress cracking failure in polyethylene films caused by a chemical was checked by means of a device, such as a "big jack" support. In this work, castor oil was used as the reagent and polyethylene films of different origins were tested. The samples used were cut out of polymer films just like those used in stress-strain study, i.e., dogbones. The stress applied in testing was caused by the dislocation of the "big jack" parallel plates. The test was run at room temperature and at 60 degrees C, in presence and in absence of castor oil. Tendency of failure is favored by presence of stress when the specimen is in contact with castor oil. Higher temperatures enhance the tendency of failure.