OK, check out this link about elder (sambucus). You have to scroll way down to find out about the toxicity.

Also, from Rodale's Illustrated Encyclopedia of Herbs:
Sambucus ssp Caprifoliacae

"The name elderberry (or elder) encompasses perhaps 13 species of deciduous shrubs native to North America and several venerable European shrubs that followed settlers here (sic, to North America).

Medicinal: Elderberry shrubs are not the place for the amateur herbal enthusiast to experiment. They contain cyanogenic glucosides, substances that release cyanide, and an unidentified cathartic, found primarily in the leaves and roots of some species.

The danger comes mainly from the roots, stems and leaves says Dr. Kenneth Lampe, author of the AMA Handbook of Poisonous Injurious Plants. (Children got sick from playing with elderberry whistles or blowguns) Ripe, cooked berries are harmless.....

Lampe says the flowers are probably non-toxic, and that limited amouts of raw fruit are generally considered to have no adverse effect."

And, from Earl Mindell's Herb Bible:

"Caution--The seeds from the raw elderberry plant are toxic; therefore, don't eat the berry unless it is cooked."

There does appear to be some disagreement on exactly which part is toxic; I can personally attest to the "laxative" effect........I prefer to err on the side of caution.