Asthma patients gather every June in Hyderabad to gulp down the fish stuffed with a yellow herbal paste, in hopes it will help them breathe more easily.

The wriggling five-centimeter (two-inch) fish is slipped into the throats of patient in a bizarre treatment that leaves them gagging.

The Bathini Goud family, which administers the treatment, says the fish clear the throat on their way down and permanently cure asthma and other respiratory problems. However, the family refuse to disclose the ingredients of their potent formula, as they claim the disclosure will mean the mixtures loses its efficacy.

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.

Rights groups and doctors have complained that the medicine is "unscientific", a violation of human rights and unhygienic, claims rejected by the family.

The Indian government arranges special trains for the "fish medicine" festival every year and extra police are on duty to control crowds.

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