Found throughout India, kalonji bushes grow to approximately half a meter and possess blue flowers. Originally from Turkey and Italy, particular effort has been made to cultivate the plant in Asia. After flowering the plant produces small black seeds about the same size as sesame seeds - they are slightly triangular in shape, and are about 40% oil, along with albumen, sugar, organic acids, glucoside melanthin metarbin and other bitter subtances, all of which combine to give a slightly peppery, vaguely nutty flavour.This explains kalonjis use in curries, dahls, as a topping for naan bread and other Indian dishes. A quarter of a tablespoon of kalonji, dry roasted in a pan for a few minutes, will add a delicious flavour to almost anything.
However, by far the most interesting thing about kalonji is its medicinal qualities, which really are quite legendary, though almost certainly apocryphal. The tongue-in-cheek declaration that kalonji is a cure for everything except death is a grand, if rather unlikely, claim. However, kalonji is rumoured to be an emmenagogue, lactogogue and diuretic. When taken with vinegar it is an anti-helminthic and its smell is rumoured to help with the common cold. Kalonji oil supposedly makes short work of alopecia, and asthmatics may find it helpful to make tea out of half a teaspoon. The toxic effects of bee and wasp stings are neutralised along with, hopefully, those less common but just as pesky mad dog bites. Paralysis, facial palsy, migraine, amnesia and palpitation have no chance against kalonji, and its use as an expectorant and antipyretic is legendary, too. Jaundice, kidney stones, inflamed gums - even haemorrhoids. Having rounded off all those, you are left wondering just what's so complicated about death that a spoonful of kalonji couldn't get you back on your feet.
The kalonji bush's Latin name is Nigella sativa, leading to the seeds sometimes being known as Nigella, though they are also sometimes known as black onion seeds. They need to be kept away from light, really, if they are to maintain their flavour. The most enjoyable way to do this is to hide them in Bombay potatoes and mercilessly devour them.