VIAGRA will make your Christmas tree stiffer for longer, researchers say.
Popping the little blue pills in a festive fir’s water supply was found to keep its branches erect for longer.
About seven million real Christmas trees are bought every year in Britain — and most drop their needles after about a month.
So researchers from Odense University Hospital, Denmark, tried to find out if plain water, aspirin or sildenafil, also known as Viagra, helped them keep it up for longer.
The erectile dysfunction drug boosts blood flow in the penis by increasing nitric oxide production.
The same chemical is also said to reduce cell damage in plants.
Adding aspirin to the water — an old wives’ tale — did not work in the study, the researchers said.
But a high dose of sildenafil had a better chance of delaying the droop compared with water alone.
Writing in the Danish Weekly Journal for Physicians, Dr Morten Ruge said: “The high-dose sildenafil group had a tendency for longer survival.”
The team cut 60 branches from a Christmas tree and stood them in water with different quantities of drugs.
They were judged on survival after 24 days and how long it took before they were considered “too ugly for Christmas”.
Branches stood in water with a high dose of sildenafil had about a 40 per cent better chance of surviving longer.
However, only the highest dose of 250mg — equal to five regular over-the-counter Viagra pills — appeared to have any effect.
Past research has found small doses of Viagra boost the shelf life of cut flowers such as tulips.
Dr Ruge added: “The result was not statistically significant but this observation is interesting as it raises a new theory.”