A child gags and squirms as he is given treatment for his asthma.

But rather than a puff from an inhaler or a pill – the boy is forced to swallow a live fish.

Every year, thousands of Indians line up to swallow the slimy sea creatures, a traditional treatment for the condition.

Asthma sufferers gather every June in the southern city of Hyderabad to gulp down the fish stuffed with a yellow herbal paste, in the hope it will help them breathe more easily.

Administered by the Bathini Goud family, the therapy is a secret formula of herbs, handed down by generations only to family members.

The clip shows the wriggling fish being marinaded in the paste, before members of the Goud family appear to stick their fingers down people’s throats to make sure the fish goes down.

They often clamp their hands over their mouths afterwards to prevent gagging, and give the neck a quick massage afterwards.

The family, who will not reveal the secret formula of the yellow paste, claim was received from a Hindu saint in 1845.

The herbs are inserted in the mouth of a live sardine, or murrel fish, and the wriggling 5cm fish are slipped into the patient's throat, often leaving them retching.

The family maintains the fish clear the throat on their way down and permanently cure asthma and other respiratory problems - if the treatment is administered three years running.

After digesting the treatment, patients are told to go on a strict diet for 45 days.

Thousands of people travel from across India for the free medicine during a two-day period, the specific dates of which are determined by the onset of the monsoon every June.

Patients employ various methods to get the fish down – which the video shows is no easy feat.

Parents are often forced to pry open the mouths of reluctant children who cry at the site of squirming fish, while others pinch their noses, tip their heads back and close their eyes.

In the clip, one girl is heavily scolded as she runs away in order to avoid having to swallow a fish.

Rights groups and doctors have complained that the treatment is 'unscientific', a violation of human rights and unhygienic, claims which are all rejected by the family.

But the crowds also appear to disagree. The Indian government arranges special trains for the 'fish medicine' festival every year and extra police are on duty to control crowds, AFP reports.