Introduction. Self-poisoning is not frequent during pregnancy. We present a successful treatment of a woman 20 weeks pregnant with twins with self-inflicted poisoning by a caustic substance. Case outline. A 34-year-old pregnant woman was admitted to our institution after self-inflicted poisoning with concentrated acetic acid. Initial clinical evaluation showed severe diffuse erythema of the mouth and oropharynx, a systemic inflammatory response syndrome, and dichorionic diamniotic twin pregnancy in the 20th week of gestation confirmed on abdominal ultrasound. An indirect laryngoscopic examination revealed severe generalized hyperemia of the laryngeal mucosa with corrosive changes in the pharyngeal mucosa, especially of the posterior pharyngeal wall. Due to pain, urgent esophagogastroduodenoscopy could not be performed, and because of the patient?s refusal a feeding gastrostomy or jejunostomy could not be created. The patient was given ?all-in-one? total parenteral nutrition in addition to other supportive therapy. Gradual introduction of enteral nutrition via a nasoenteric tube placed in the second month of hospitalization failed due to severe vomiting. After almost three months of total parenteral nutrition, enteral nutrition was nevertheless introduced; we then started with oral fluids, increasing gradually to a regular diet, and needed almost half a month to reach the adequate nutritional goal. The delivery was spontaneous at the 36th week of pregnancy and the patient gave birth to two normal healthy girls (46 cm / 2,580 g and 48 cm / 2,960 g, respectively). Conclusion. Total parenteral nutrition can be a safe choice for providing prolonged and adequate nutritional intake even in a twin pregnancy without adverse effects on fetal growth.