Many of these products can contain illegal substances such as heavy metals, the ingestion of which can cause harm to an individual over a period of time.
Gall llawer o'r cynnyrch hyn gynnwys sylweddau anghyfreithlon fel metelau trwm, a gall llyncu'r sylweddau hyn achosi niwed i unigolyn dros gyfnod o amser.