An Australian man who tried to smuggle cannabis into a prison cell inside a balloon up his nose was stunned when doctors retrieved the illicit package – 18 years later.

The unnamed 48-year-old patient’s girlfriend gave him the drug-filled balloon during a prison visit and the man stuffed it into his right nostril to hide it.

He believed he had swallowed the package when he was unable to retrieve it, according to a paper published in the British Medical Journal.

The report stated: “In order to evade detection, the patient inserted the package inside his right nostril.

“Despite effectively smuggling the package past the prison guards, [he] then accidentally pushed the package deeper into his nostril and mistakenly believed he had swallowed it.”

The cannabis was wedged up his nose

Over the years the balloon slowly developed into a rhinolith – a stone in the nasal cavity that forms around a foreign body because of a build-up of calcium and magnesium salts.

The patient suffered regular sinus infections and breathing problems but only sought medical attention when he started getting severe headaches.

Doctors performed a CT scan and discovered a “rubber capsule containing degenerate vegetable/plant matter”.

It was surgically removed and, three months later, the patient reported that all the symptoms had disappeared.

The team of researchers believe the case is the first report of smuggled cannabis becoming a rhinolith.