To reduce the gastric capacity and cause significant weight loss in rats without developing anemia, a surgical procedure was performed, similar to that described by Tolosa et al.30. After 12 hours of fasting, the rats were anesthetized by isoflurane 4% vaporization. Anesthesia was continued through a mask with 1.5-3% isoflurane inspired fraction, and the rats were submitted to median laparotomy and gastrostomy in the greater curvature of the stomach for the implantation of a cylindrical Luffa bush (loofah; 1.5 cm in diameter) made of cylindrical Luffa (an experimental phytobezoar). The gastrostomy was closed with continuous mononylon suture yarn 6.0, and the abdominal wall was closed in two planes: the aponeurosis, with 4.0 mononylon suture yarn, and the skin, with 3.0 plain cotton stitches. The animals in the sham group were exposed to the same surgical procedure described above but were not submitted to phytobezoar implantation. Tramadol hydrochloride (20-40 mg/kg) was administered intraperitoneally, with a frequency of at least 12 hours for 5 days31.