Police are investigating a naturopath whose recommendations to the parents of a four-year-old autistic boy left the child hospitalised with sever hypercalcaemia. The unnamed child had reportedly been vomiting and constipated for three weeks, losing three kilograms in weight.

The boy was taken to accident and emergency where he was diagnosed with hypercalcaemia – high levels of calcium - which has been known to cause cardiac arrest in severe cases. The 4-year-old made a full recovery after two weeks.

Parents of the boy told after doctors about a cocktail of supplements he had been taking after three days in hospital. The naturopath now being investigated had told the family to give the child 12 different supplements which included vitamin D, zinc, calcium and camel's milk, The Guardian reported.

Doctors from Barts Health NHS Trust, where the boy was treated, wrote in the British Medical Journal that though so-called natural remedies can be seen as a "safer" option, "there can be significant adverse effects".

"His parents were devastated that something they had given to their son with good intent had made him so unwell."

Speaking to the paper, Jane Harris from the National Autistic Society said that it is "crucial" doctors speak to families about the potential risks of alternative therapies: "This awful case shows we need more professionals in place to give families accurate advice and talk to them about what really helps and how to find the right support."