The Ministry of Health has issued a warning over four unapproved medicines made in Samoa and Tonga and sold in New Zealand.
Director-general of health Stephen McKernan says three of the medicines are labelled as originating from Maria's Healthcare Multipharm in Apia, while the fourth product appears to be from Tonga.
Mr McKernan says the safety and efficacy of the products - Multipharm Fluid Magnesia, Vai Lafa for ringworm, Vai Tane for fungal infections and Vaikahi Mixture for bloating and constipation - are not known.
He says medicines must be assessed and approved for treatment and labelled in English before they can be sold in New Zealand.
The head of Pacific Health at Auckland University says health remedies need to meet certain standards.
Teuila Percival says without testing, the efficacy and contents of the remedies cannot be known.
The Tonga Advisory Council says people should consult a doctor or pharmacist if they are unwell, instead of going to their grocery store to buy an unproven remedy.
Medsafe is investigating the matter.