This article is more than 16 years old

This article is more than 16 years old

We knew it gave people the munchies and made them giggle. Now researchers claim to have found a new property in cannabis - it helps us see in the dark.

Scientists made their discovery after becoming intrigued by Moroccan fishermen who not only failed to lose their sense of direction after smoking generous amounts of local kif, a mixture of cannabis and tobacco, but seemed to navigate better on dark nights.

"They attribute their ability to see to the consumption of kif that they spend entire hours smoking before getting into their barques," one of the research team, drawn from the US, Spain and Morocco, reported.

Jamaican fishermen have reportedly shown a similar reaction, suggesting that there may be something medically useful in cannabis apart from the pain-deadening properties already spotted by doctors treating cancer patients.

Equipped with a machine for measuring night vision, the researchers headed for the Rif valley, the centre of Morocco's flourishing cannabis trade. "High-grade sifted cannabis was mixed with tobacco in a 2:1 ratio and smoked as kif by subjects employing a traditional sebsi pipe," the team write in the latest Journal of Ethnopharmacology.

Three "kif-experienced" Moroccan volunteers were then invited to make "numerous inhalations".

The volunteers demonstrated "consistent improvements" in tests, leading the researchers to suggest that further studies should be conducted.

The researchers admit that the results have turned the ancient wisdom of Persian and Arab scientists, who suggested that cannabis made vision fuzzier, on its head.

But their results backed up claims by the Observer columnist Sue Arnold, who suffers from retinitis pigmentosa and is officially registered blind. She noticed several years ago that drawing on strong Jamaican skunk suddenly and temporarily enabled her to see things clearly.

But Ms Arnold has since warned of side-effects that could impede night-time navigation.

"Only trouble was," she said, "I couldn't stand up."