Online dating explained by nitrous
Nitrous oxide is a colourless, sweet tasting gas that has been used recreationally since the late 18th century, most notably by Sir Humphry Davy, former president of the Royal Society.
Medical use was established in the early 20th century and nitrous oxide remains an important anaesthetic, tranquilliser and painkiller, used by dentists, obstetricians and sports doctors.
Risks can vary, depending on how the drug is administered.
Inhaling nitrous oxide directly from a pressurised canister can damage the lungs.
Indeed, many members of the public will have experienced the effects of nitrous oxide themselves without realising it.
For example, the introduction of ash into the soil raises the soil's p H, which in turn raises the content of a variety of nutrients, especially phosphorus, for a short period of time of around two years.
And, although rare, a few people have died from asphyxiation after passing out while their mouth and nose are connected to a tube or surgical mask, or where a bag containing nitrous oxide has been placed over the head.