Somebody once told me that superglue contains cyanide or some deadly substance.
The drink was found to contain cyanide.
The powder in the bottle contained cyanide of mercury.
The powder was later analyzed, and found to contain cyanide of mercury.
The seed contains too much cyanide to be edible, but see under Paleobotanical evidence below.
I sure as heck didn't know it contained cyanide.
The seeds contain cyanide, which suggests that quince seeds might not be safe.
The apple seeds, however, contain cyanide and are poisonous.
It contains cyanide, particularly in its growing shoots.