What is japanese for toxic?

My friend likes the word so i'm trying to find it for her. But so far nothing. I can't find it.

You mean "toxic" as in toxic substances, etc., meaning "harmful" ?
"Yuugaisei," "chuudokusei," "dokusei," etc. are the words that come to mind,
but those really do sound chemically harmful and dangerous!

Sayoko,

Try "doku" or "yuugai". AK gave you the nouns (toxicity) rather than the adjectives.

By "toxic", doesn't your friend mean "awesome" as in the teenager's term? If so, non of the expressions given will fit the needs. I can't think of an almighty word that is equavelent to "toxic", so if you can give us some context that might help. I mean, "maji-sugee" would sound too un-cool.