However, the substances themselves only rarely cause long-term damage to the body.

Some substances cause cancer primarily through their physical, rather than chemical, effects on cells.

Many substances will not cause damage if they are flushed out of the eye quickly.

These substances can cause an attack in a person who has asthma.

Many foreign substances, including glass, nylon and metal, also cause cancer in this particular species.

Many medicines and other substances can cause changes in how we feel.

Even substances such as milk, which pose no risk to human health, can cause serious harm to the water environment.

Different substances cause other adverse effects that may be severe.

We all know what these substances cause, for example skin cancer and eye damage.

These substances are usually found indoors and do not cause symptoms for most people.