In message , Kath
writes
Are the berries of the Guelder rose edible? They are so pretty that I
suspect they are not
which would be a pity because there are loads around here.

There's lots of web pages around saying that the fruits are of zero to
low toxicity, but if consumed in large quantities cause vomiting and
diarrhoea. (Smaller doses may cause stomach upsets.)

However, Jones and Wheelright, Seasonal changes in the fruits of
Viburnum opulus, a fleshy-fruited temperate-zone shrub, Can. J. Bot. 65:
2291-2296 (1987)
(URL:http://www.bowdoin.edu/faculty/n/nwheelwr/pdf/Seasonalchanges.pdf)
says "The fruits are apparently chemically defended and mildly toxic and
have a bitter, sour taste", citing a 1972 Ph.D dissertation.

So, I conclude that they're not edible due to the bitter taste.
--
Stewart Robert Hinsley