3-Dimethylaminopropylamine (CAS No. 109-55-7) was evaluated for subchronic oral toxicity in groups of Wistar rats (5/sex/group) administered doses of 0, 10, 50, and 250 mg/kg-day by oral gavage for 28 days. Due to a high rate of mortality (3/5) among the 250 mg/kg females during the initial study, a second trial in 5 female rats receiving 250 mg/kg was conducted with data combined for 10 high-dose females. All animals were necropsied on the 29th day of study. Females of the high dose group only (4/10) died during the 28-day treatment period. Clinical signs, observed intermittently in this group between study days 11 and 24 and mainly among the intercurrent decedents, included hypoactivity, stilted gait, swollen abdomen, and labored breathing. A solitary high-dose male demonstrated impaired respiration. Bodyweights, organ weights, food and water consumption, urinalyses, and hematological and clinical chemistry evaluations did not deviate significantly from those of controls in any dose group. Upon necropsy, discolored lungs with surface red spots and foamy content, and a solitary small spleen characterized the gross pathology identified solely in the decedent females. Microscopic examination revealed distinct lesions among these animals, which included organ congestion, hemorrhagic and/or edematous lungs, and profound loss and atrophy of splenic lymphatic follicles and lymphoid sheath, respectively. One symptomatic male of a 250 mg/kg dose group exhibited focal epithelial degeneration of the forestomach which authors claimed was likely due to an irritative effect of the compound.