When the bananas failed to produce the desired effect, police fed Sheikh Mohsin rice, chicken and local bread.
Finally the necklace, which appeared on an X-ray taken on the suspect, was excreted and retrieved.
Mr Mohsin will appear in court on Monday in the eastern city of Calcutta, and could face a prison sentence.
Police say he snatched a gold necklace worth £550 ($1,100) from a woman as she shopped for toys on Saturday.
When cornered by police, he swallowed the necklace.
The suspect was fed 50 bananas on doctor's advice, after the X-ray dealt a blow to his denials.
But only after a further meal did he yield the necklace, Calcutta police deputy commissioner Gyanwant Singh told AFP news agency.
A sweeper was paid to retrieve the exhibit from the toilet. Mr Mohsin was asked to wash it.
source: BBC South Asia
