Background: Drugs used in preterm labor (PTL) have side effects. Research into new tocolytic agents is recommended. The plant Bryophyllum pinnatum (Lam.) Oken (Kalanchoe pinnata (Lam.) Pers) is used in Anthroposophic Medicine for PTL, insomnia, and emotional disturbances. The aim of this study was to evaluate the effects of B. pinnatum mother tincture (MT) on Wistar rats and their fetuses throughout pregnancy. Method: Sixty animals were divided into 6 equal groups: controls C1 and C2 received 1 and 25 × the maximum daily dose of a 30% ethanol / water solution, serving as vehicle of B. pinnatum MT; B1 and B2 received 1 and 25 × the maximum daily dose of B. pinnatum MT; and B3 and B4 received 50 and 100 × B. pinnatum concentrate. The following parameters were assessed: weight gain; maternal and fetal mortality; implantations and resorptions; number and weight of fetuses and placentas; major external fetal malformations. Results: Rat weight gain (excluding fetal and placental weight) was higher in group B4 and lower in group B2. There were no maternal or fetal deaths and no group differences in implantations and resorptions or number and weight of fetuses and placentas. No macroscopic fetal abnormalities were observed at the 4 dosage levels investigated. Conclusion: Daily administration of B. pinnatum MT at high doses to pregnant Wistar rats interfered with maternal weight gain and did not interfere with fetal compartment.