Europe, temperate Asia and North America
"Numerous frugivorous birds eat red elderberry fruits. In the Northeast, at least 50 passerine and 6 game bird species consume the fruits. Red elderberry fruits are also important in the diets of game and nongame birds in the West. An Idaho study found red elderberry fruits were a major summer diet item of blue grouse in Douglas-fir habitats. A study across western Oregon found red elderberry fruits were the main summer diet item of band-tailed pigeons. Mammals, including eastern fox squirrels, white-footed mice, other rodents, northern raccoons, American black bears, brown bears, and grizzly bears, also consume red elderberry fruits. Additionally, grizzly bears consume red elderberry foliage and roots.
Browsing ungulates consume red elderberry foliage, although red elderberry browse is not preferred on all sites. The browse contains cyanide, which is bitter, so red elderberry use may be light in areas where more palatable forage is available. Use may be heavy, however, in areas with large white-tailed deer populations. In winter, browsing ungulates consume red elderberry bark and buds; although even then, browsing may be light if other shrubs are available. Red elderberry provided minor winter forage for moose on Isle Royale, Michigan and was not preferred as summer browse. In contrast, by the Flathead River of Montana red elderberry was "easily the most palatable browse species on the range". Red elderberry was not abundant, and with 70% utilization by elk, it was apparently in decline. Studies in coastal Alaska and the West coast found Roosevelt elk consumption of red elderberry peaked in fall (16% of total diet) and was least in spring (1% of diet) (review by).
Common porcupines, mice, and snowshoe hares consume red elderberry buds and bark in winter.
Various fly species consume red elderberry pollen. Red elderberry and Mexican elderberry (Sambucus mexicana) are obligate hosts of the federally threatened valley elderberry longhorn beetle, which is endemic to the Central Valley of California." 
"Red elderberry fruits are used to make pies, jelly, and wine. The fruits contain anthocyanins, which have antioxidant properties. The fruits are sour, however, and people do not usually eat them raw. The fruits and/or seeds may cause diarrhea and vomiting in humans, especially if the fruits are not fully ripe. Other parts of the plant may be poisonous to humans year-round. Native Americans used red elderberry fruits as food and extracts from the roots and/or bark as an emetic or purgative , review by) and to treat colds. Native Americans also used bark extracts as a gynecological medicine and to treat influenza, fever, and tuberculosis. The stems were used to make toys. The Dena'ina made popguns from the hollow stems, using a shelf fungus (Polyporus betulinus) for ammunition. The Kwakiutl of British Columbia made toy blowguns from red elderberry stems.
Red elderberry is planted as an ornamental.
Extracts from red elderberry roots exhibited antiviral activity against bovine respiratory virus in the laboratory." 
"Red elderberry is used in revegetation, erosion control, and wildlife plantings. It may be relatively tolerant of heavy metal contamination; red elderberry was among a few relict shrub species present on acidic copper and nickel mining and smelting sites in Ontario. Red elderberry is easily started from cuttings and is often grown from seed. Commercial sources of red elderberry are available." 
 Fryer, Janet L. 2008. Sambucus racemosa. In: Fire Effects Information System,. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: https://www.fs.fed.us/database/feis/plants/shrub/samrac/all.html.