Why Megan Gale believes in salt therapy.

Moments after model Megan Gale posted a photo of her nine-month-old son River on Instagram, the criticism began flooding in.

The 39-year-old had taken River in for a salt therapy treatment in Melbourne’s Frankston.

“Little man all congested and blocked up with a cold. Clearing out the sinuses in a salt therapy session at @saltsoftheearth,” she captioned the Instagram shot.

The alternative therapy originally comes from Roman and medieval times, when those working in salt mines had less respiratory issues. The treatment claims to help relieve inflammation, congestion and allergies from the respiratory system and skin.

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Inside a salt room. Pic:

Salts of the Earth, the clinic Megan visited, says that by sitting in a room which is designed to mimic a salt cave, the inhalation of minute particles of pharmaceutical grade salt deep down into your respiratory system draws out the inflammation, and then breaks up mucus and congestion. It can reportedly benefit people of any age with respiratory and skin ailments.

Many of Gale’s 237,000 fans were supportive, while others were quick to criticise in comments that have now been deleted from her account.

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“Could be one of those B.S. alternative treatments but I’d give it [a] go if someone pays it for me. I rather go to the beach, it’s free! Ha!” One Instagram user said.

“Don't bother. There is absolutely zero evidence they have any therapeutic effect. Maybe for celebrities who have tooooo much money,” another commented.

Asthma Australia issued a warning in 2012 that there is no credible medical evidence that salt therapy works, and it can even be dangerous for some asthma sufferers.

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"The most dangerous thing you can do if you have asthma is to stop taking your medication,” reads a statement on the organisation's website.

“If you’re interested in trying alternate therapies for your asthma, find yourself a doctor who you can talk to about it, and who will help you stay safe while testing its effects.”

As many mothers know, there's not a lot you can do when babies under one are sick. We hope the little guy is on the mend.

What do you think of salt therapy?