The corn cockle is a native of Europe and is believed to have arrived in Britain on the backs (possibly quite literally) of Iron Age farmers, as it grew among crops of grain such as rye, which seems to have been its favourite neighbour in Britain, wheat and barley. Like the red poppy and blue cornflower, it flourished in cultivated land. Now it is a very rare sight in the wild in Britain , but can be bought for gardens.
It is a member of the pink family of plants so is related to carnations, cloves, soapwort (Saponaria officinalis) and the soapnut or reetha. The seeds and roots of the plant contain saponins which are toxic and so should not be eaten. However leaching (soaking in several changes of water for a day or so) generally rids plants of their toxins. It is said that the leaves of the corn cockle may be eaten as a vegetable in times of famine.
The plant was extremely common in agriculture land in Shakespeare’s time and earlier, and seeds have been found in cess pits at York and other archaeological sites in Britain . It has been suggested by some that the seeds were an adulterant of bread, which like ergot, a fungus, could have lead to debility and made the population in the Middle Ages susceptible to leprosy a common disease at that time. This was discussed in 1961 by Professor Harry Godwin and K. Bachem. John Gerard writing in the 16th century said that the corn cockle was often to be found in bread which it spoiled.
“This unprofitable guest amongst corn is of Saturnine quality, causeth giddiness of the head, and stupefies if it gets amongst the corn to be made with it into bread, and, howsoever taken, it is dangerous and hurtful; although some ignorant persons have mistaken it for the right nigella, or used it instead of yuray or darnel to the great danger of the patient.” (“right nigella” is nigella sativa from which we get kalvanji or black seeds)
However the Welsh Physicians of Myddfai have it in one of their remedies for pneumonia, taken along with other herbs: -
“Let (the patient) take, for three successive days, of the following herbs; hemlock, agrimony, herb Robert, and asarabacca, then let him undergo a three day's course of aperients. When the disease is thus removed from the bronchial tubes, an emetic should be given him (daily) to the end of nine days. Afterwards let a medicine be prepared, by digesting the following herbs in wheat ale or red wine: madder, sharp dock, anise, agrimony, daisy, round birthwort, meadow sweet, yellow goat's beard, heath, water avens, woodruff, crake berry, the corn cockle, caraway, and such other herbs as will seem good to the physician.”
It gets a mention in Shakespeare’s “Coriolanus” in Act III scene I when Coriolanus and other senators are discussing a recent gift of corn to the poor, and liken them and their ingratitude for the gift to the “cockle”
“Coriolanus: …In soothing them we nourish ’gainst our senate
The cockle of rebellion, insolence, sedition,
Which we ourselves have plough’d for, sow’d and scatter’d,
By mingling them with us, the honour’d number.”
In the Middle Ages the seeds from the corn cockle were prescribed by the apothecaries of the time as a laxative and were more harmful than jamalgota. In folk medicine systems in Europe the seeds were prescribed for treating cancer and tumours, as well as for hard swellings of the uterus (apostemes). The saponins were responsible for the local anaesthetic uses of the plant, but the seeds cause acute poisoning if taken in large doses resulting in vomiting, vertigo, difficulties in breathing, diarrhoea and excessive salivation, amongst other symptoms. The seeds contain githagenin which can get rid of intestinal worms, but the plant is best left alone and admired as a garden ornamental. If you do plant these in the garden, they need support as they can grow quite tall and bend under their own weight, producing a solitary flower which is pink-purple at the top of the spindly stem.