They claim that many toxic substances, even in low concentrations, can act together to cause much more harmful effects than each substance would individually.

However, some substances act as diuretics causing the kidneys to process water faster than plain water.

This risk is especially high when that substance acts like a hormone, and you take it over a long period of time.

Both substances act to block the absorption of sulfur by the washcoat.

Various other substances act together to activate plasmin and help it break down the blood clot.

Some substances act both as allergen and irritant (wet cement, for example).

In principle a substance could temporarily act as both.

These substances act as weak estrogens and block the action of natural estrogen in some tissues.

These substances act as a fertilizer for the bacteria and help them grow at an increased rate.

These biochemically active substances accompany vitamin C in plants and act as an antioxidant.