The Universal Church of the Kingdom of God has been handing out cross shaped vials of a "holy oil" which it says have been blessed in Jerusalem and can "activate people's faith" in order to treat medical conditions such as depression, addiction, heart problems and chronic pain.

One testimonial was from a man who said he was "cured after 11 years of heart problems and being told he had only a month to live."

The church has attempted to indemnify itself by making the claims through people's testimonials, and offering a disclaimer:

"The UCKG does not claim to heal people but believes God can through the power of faith. Always follow your doctor's instructions."

Unfortunately experience has shown me that testimonials are not an accepted way to make therapeutic claims in New Zealand without needing to prove that your product works, and a disclaimer such as this does not protect you from the law when you've made claims of efficacy. There are examples in NZ of churches who have made similar claims in the past, and the Advertising Standards Authority has normally ruled against them when complaints have been made.

It's very easy to be fooled into thinking that an ineffective treatment is working for you. People generally only report when a treatment appears to have worked, and tend to stay quiet when it doesn't - this makes others think the treatment always works. For many conditions, they will go away of their own accord after a while - and people will think that it's the treatment that helped them. There are many other reasons for treatments to look effective, but these two alone are enough to give a convincing false positive.

Only proper double blind testing will help to ensure that people aren't being fooled - anything less than this is probably a waste of time.

Cate Thorn of St Matthew's in the City, a liberal church in Auckland, said:

"I think, at the end of the day it's not really anything to do with oil at all. It's a marketing campaign that's sent in order to cause a reaction among those who receive it."

She also said if people felt they were being promised a solution for their problems which didn't work, then the church could be causing emotional distress.

I predict that the church will likely see one or more complaints made against them soon, probably to the Advertising Standards Authority.