The Ministry is reminding people with these conditions that these products have not undergone the same level of clinical assessment as medicines prescribed by doctors.
It said prescribed medicines should not be stopped unless there's advice from a doctor or nurse.
A statement from the Ministry said most of the products are promoted, sometimes untruthfully, as cures or health aids for patients.
It said the products were often expensive and for this reason people think they must be good.
The ministry said hospitals around Vanuatu have seen many cases of amputations because regular prescribed medicines for diabetes have been stopped while people use these products.