Introduction: Little is Known about the natural history of gallstones left behind in the peritoneal cavity during 
laparoscopic cholecystectomy . 
Aims: This experimental study was conducted to assess the consequence of implanted intra- abdominal gallstones in 
dogs. 
Materials and methods: Eighty four male mongrel dogs were divided into: G1 (n =12), G2 (n=36) and G3 (n =36) Where 
sterile glass beads with sterile saline , collected bile with different types of gallstones (subgroups) and enriched bile 
(E.Coli & Staph. aureus) with gallstones were implanted in an omental pouch respectively. 
The gallstones and bile were collected from 50 gallbladders resected from patients with chronic calcular cholecystitis. 
Half the number of dogs from each group was re- explored after one week and the rest after six weeks, so as to retrieve 
the implants with their surrounding tissues for histopathological examination. 
Acute inflammatory reaction with different degrees of intensities of polymorphonuclear leucocytes and macrophages 
were noted in G1 and G2 after one week which completely disappeared six weeks postoperatively. In G3, severe acute 
inflammatory reaction and abscess formation were observed one week postoperatively, but markedly resolved in animals 
explored after six weeks without antibiotic coverage. 
Conclusions: This study revealed that intraperitonal lost gallstones cause no serious tissue reaction in dogs. We suggest 
that lost gallstones during laparoscopic cholecystectomy, unless easy to retrieve, should not prolong the operation time or justify conversion to laparotomy.