Marijuana contains known toxins and cancer-inducing chemicals, which are stored in fat cells for long periods of time.

Pathogenic C. difficile strains produce several known toxins.

V. cholerae non-O1/O139 strains may cause gastroenteritis through production of known toxins or unknown mechanism.

Some strains of these species produce known toxins, but the pathogenic mechanism is largely not understood.

A study commissioned by the regions health authority, found that several known toxins and carcinogens were elevated.

Melamine is not a known toxin.

Botulinium toxin is one of the most powerful known toxins: about one microgram is lethal to humans.

For 70 years, we put a known toxin, one especially harmful to children, into hundreds of millions of machines, which turned it into a fine aerosol, easily inhaled.

Bromoform, produced by several algae, is a known toxin, though the small amounts present in edible algae do not appear to pose human harm.

Fortunately, the toxicity of Nertera granadensis appears to be quite low, and there are no known toxins associated with the particular parts of the plant.